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alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

1 edit

Generator house link project - The progress.

So I've made several threads inquiring about different aspects of linking my generator to my house and that project changed a lot over time.

Now that I've began work on the actual project, I'll be keeping this thread up to date with the progress and post pictures.

The progress

The trench
My original plans consisted of two raceways, but I had to limit it to one trench.... here's why:

What a pain in the ass that was. I did rent a trencher, but my land is a freaking quarry! one or two inches deep and I hit rocks.

Below is the picture of rocks that I took out from a 4 feet portion of my trench. And yes that's a full size pickaxe.



There's another accumulation of stones like that on the other edge of my trench (another 4 feet) and pretty much one big stone per foot on average on the rest (8 feet)

You'd think "okay" depends the depth and width of the trench right? 4 feet of length can mean anything in depth and width.
Well, it's only 17 inches deep. The picture here pretends its wide, but that surface width, it's mostly 2-3 inches wide at the bottom.



So basically I had to pass 4 or 5 times with the trencher, every time removing the layer of stones that it couldn't pull up. It's actually freaking hard to pass a trencher over an existing trench as it kept falling into it. Try handling that alone with a 400lbs trencher that isn't self propelled.

The raceway
I'll be editing this part to add pictures tonight or tomorrow.

Basically the raceway consists of schedule 40 3/4" PVC. It will come up to the house through the concrete foundation under my main floor, over my basement ceiling, which had to be removed ANYWAY for renovations). The hole will be drilling through a pre-existing abandoned telephone POTS entrance. Of course, not same size, but by drilling from the outside, I will know where exactly it exists in advance.

Finished worked later today, or tomorrow (I got Monday and Tuesday off). Then I'll post pics.



Inside will be 6 conductors, consisting of 2 sets of Hot/Neutral/Ground RW90 10AWG. One set will be linked to my generator with a L5-30R twist-lock connector. The second set is disconnected/unused. If I upgrade to a 6000W generator, which often split their load over two 30A outlets, then I'll have a second set of conductors available. CEC allows multiple runs in raceways as long as it comes from the same power source and that I respect the limit of gauge/amp conductor per raceway width.

The house wiring

A transfer switch [That's what it will be and I'll post pictures when I'm at that step].
And probably this transfer switch: »www.homedepot.ca/product/60-amp-···s/901372

Those of you who know how my plans started, you'll wonder why I've FINALLY went with a transfer switch instead of having separate circuits for the generator. Well as my budget grew for properly doing the project and my knowledge on the matter increased exponential, I realized a few things:

1 - A transfer switch won't be that hard (anymore) to install.
2 - My current 3000W (4000W peak) generator could actually run my gaz furnace AND refrigerator as long as my gas furnace blower was left ON, so there is no risk of peak watt requirements at the same time as the fridge.
3 - To actually link my furnace to the generator, it would actually cost another 50$ in material if I were to make it that I can unplug/plug it to different circuits.
4 - Material to create different circuits around the house just for the generator would also cost $$$$.
5 - Eventually the price difference between a transfer switch and a subpanel became justified, as with a transfer switch, extra expenses related to point 3 & 4 would be unrequired.


nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12

3/4"? You are shooting yourself in the foot there my friend. Conduit is cheap. Trenching is expensive.
--
I just might be the most "licensed" S.O.B. you know.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by nunya:

3/4"? You are shooting yourself in the foot there my friend. Conduit is cheap. Trenching is expensive.

I know I could upgrade, but I don't see why.

It's not like I can run wires for OTHER purposes in there no matter the width. All I could do it run more wires for the same purpose, meaning a BIGGER generator than 7200W.

At that point, a bigger generator would probably not allows connecting 3 sets of conductors, hence I'd need to pull out all the wires and place bigger gauge.

And eventually if I do go so huge, it would be a natural gas generator... which cannot be at my shed, it has to be right next to the gas line which is pretty much against my house wall (hence no more conduit).

But then again, I don't know what you know. What should I put and why? (PVC tubes are bought, but can be exchanged, nothing is set).

W5JGV

join:2001-02-03
Natchitoches, LA
Reviews:
·WildBlue

said by alkizmo See ProfileAnd eventually if I do go so huge, it would be a natural gas generator... which cannot be at my shed, it has to be right next to the gas line which is pretty much against my house wall (hence no more conduit).

But then again, I don't know what you know. What should I put and why? (PVC tubes are bought, but can be exchanged, nothing is set).[/BQUOTE :

From personal experience -

1) If you do it yourself, gas line (plastic) is cheaper than wire. Bring the gas to the genset.

2) Any conduit you bury will be too small.

I burned myself with that when I installed the power able from my house to the Hamshack/Art studio outbuilding. I buried conduit that I was sure was large enough. It wasn't. It was, shall we say, "snug." I wound up using a block and tackle to pull the cable through the conduit and around one 90 degree bend.

3) Any genset you figure will handle the load will turn out to be unable to handle the load you have next year. (See #2)

I went from a 5 KW to 27 KW when I moved here. "Surely, that will be big enough!" I said to myself. Nope. I managed to drag it to a halt when I kicked on the house and outbuilding loads at the same time. I had forgotten that I had added a new electric water heater and 10 KW of resistance heat in the outbuilding. So I am back to load management when the commercial power fails.

YMMV - have fun!



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

From what I remember, ng generators need to be close to the counter as the pressure becomes very low.

If I go over 7kw I would need a better shed

I put the generator in my shed so it is more quiet and locked away while operating so it doesn't get stolen. A 2000$ generator warrants a more "attached to house" setup to prevent theft ( if the weight alone doesn't cut it)

My house panel is 100 amps. The dryer and stove make up the extra 40amps between what my raceway can handle (60a) and the house panel.
I'm not planning on using either during a power outage. Doing so would
require way wAy more equipment to support 240v and a bigger transfer
switch.

You guys tell me to go bigger. I am already doubling the capacity compared
to what my generator can handle. How big should I go? because as I said,
if I went bigger than 60a, it run a Gas genny from the outside wall of my house without raceway.

If only you were mOre specific



PoloDude
Premium,VIP
join:2006-03-29
Northport, NY
kudos:3
reply to alkizmo

Man you are going to kick yourself in the ass for using 3/4" conduit. Save that for whatever spare cables (data,AV whatever) you may want to have in the future.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to alkizmo

Guys just say how big PVC I should use. Not just "bigger"



Msradell
P.E.
Premium
join:2008-12-25
Louisville, KY
reply to alkizmo

I would probably go with at least 2".



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting
reply to alkizmo

From what I gather, it sounds like you intend on possibly paralleling small conductors either now or in the future.
I *highly* doubt the CEC allows paralleling small conductors as you intend. The reason I say this: It goes against common sense and good electrical practice. I just sat through a very boring class on the 2011 NEC changes. Why were there so many changes this year? They are "lining up" the CEC and NEC. At this point, there aren't many vast differences.

Just because code says you can cram X number of conductors in Y size pipe, it doesn't mean you should. I've always found a good rule of thumb when it come to small conductors is upsizing by one trade size for whatever the code dictates is the minimum. Remember, code is the "bare minimum". Not the gold standard.

That being said; over a 50' trench, using 1-1/4" instead of 3/4" would cost you $13.00 more. That's based on 50' sched 40 PVC, 2 LB's, and 2 90's. So, that's an extra $26.00 for two pipes.

Considering the trench is open, it would be foolish to throw 3/4" pipe in there.
--
I just might be the most "licensed" S.O.B. you know.



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:6

1 edit
reply to alkizmo

You could get by with 1" PVC conduit, but I'd make it 1-1/4" PVC to increase the crush resistance due to all the rocks.


W5JGV

join:2001-02-03
Natchitoches, LA
Reviews:
·WildBlue
reply to alkizmo

NG gensets will require a larger diameter gas line if they are a long way from the meter. The meter size may need to be increased if the genset draws too much gas. My genset runs on Propane, so I went with a 10 PSI underground plastic pipe feed system and a secondary regulator from 10# to 14" WC at the genset. The underground run is about 150 feet.

Lockdown of the genset to keep it from "walking" is a good idea, esp. if it is portable. Bolting it to a concrete slab with security bolts works well, too. My genset weighs 1500# and is bolted to a 1500# slab, so it'll probably stay where it is.

Realistically, most folks can get by with less than everything powered. The user just needs to decide what they MUST have, and what they would LIKE to have on the genset, and plan accordingly. I do have plans to load shed in case an extended power outage happens, for instance, an ice storm. The last time that happened here a few years ago, this area was without power for over three weeks.

Ideally, your transfer switch should be able to handle the full load of your service entrance. That way you don't have to split circuits, although you can certainly open breakers to power less than everything if your genset can't support the full load. That being said, the price jump between 100A and 200A transfer switches is staggering. As me how I know! There's not much point in buying a switch larger than your service entrance is rated for, unless you plan to upgrade your electrical service in the future.

BTW, I have determined that my 27 KW genset uses less fuel when it is loaded to 8 KW than my 5 KW genset uses when it is running loaded to 5 KW. Bigger engines are more fuel efficient than small engines. And 1800 RPM machines are more fuel efficient than 3600 RPM machines.

Re conduits, I would run separate conduits for power and control/data lines. IIRC, it's against code to put them in the same conduit, and in any case, you don't want data lines running right next to power wires. As for conduit size, unless you plan to run the correct wire size for the largest genset you might install later, I'd use about a 40% fill for figuring conduit size. That assumes no more than two 90 degree bends. Control and data conduits - I personally like 30-40% fill to allow for future additions. That also lets me leave a length of poly pull rope (rope, not line - line gets fouled on the existing wires too easily) so I can pull in wires at a later date.

Every installation is different, and everyone's requirements are different, so just do what works out best for you. My installation was done the way I did it because of prior experience with power failures and my at the time needs, combined with what I thought I would need in the future. So far, I gave come out about 80% correct.

Have fun!



jack b
Gone Fishing
Premium,MVM
join:2000-09-08
Cape Cod
kudos:1
reply to alkizmo

Why don't you design it for 240 volts to start with: go with 2 hots a neutral and ground?

You're unnecessarily limiting yourself with a 120 volt circuit. I'd run 4#10 conductors and 30 amp L14-30p plug connectors. If you only want 120 volt only use 3 conductors for now.

If you're planning on attempting pulling or pushing those cables in pvc, don't go under 1-1/2 inch diameter.

And do yourself a favor and don't backfill the trench until after the wire is run in the pipe.
--
~Help Find a Cure for Cancer~
~Proud Member of Team Discovery ~


peterboro
Avatars are for posers
Premium
join:2006-11-03
Peterborough, ON
reply to alkizmo

said by alkizmo:

2 - My current 3000W (4000W peak) generator could actually run my gaz furnace AND refrigerator as long as my gas furnace blower was left ON, so there is no risk of peak watt requirements at the same time as the fridge.

I'm sure you covered this in previous threads but I can run a natural gas furnace and fridge with a 1200W. This isn't a theoretical premise as I have used the gen several times during power outages with both and didn't have to keep the fan on.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

1 edit
reply to nunya

said by nunya:

From what I gather, it sounds like you intend on possibly paralleling small conductors either now or in the future.
I *highly* doubt the CEC allows paralleling small conductors as you intend. The reason I say this: It goes against common sense and good electrical practice.

Code says I can cram 9 10AWG conductors in 3/4.
I could go 1 1/2 I guess, just for "good measures" and having a lot of space to re-run wires through it (large gauge are extremely unflexible after all).

Another user said 2" but those cost 3x as much as 3/4" and well.... some people say I can run other stuff in there... but I'm with you Nunya, on the fact that I shouldn't run other things in there.

As for paralleling small conductors... what choice do I have aside from running two trenches? By code, if I were to run two raceways, they'd need to be 12 inches apart, that's pretty much a second trench, unless I'm using an excavator. Portable trenchers would only fall into a ditch any wider than what they create.

I can't find 6000W-8000W portable generators that allow outputting all power through one outlet, thus using only one set of conductors.

They all split into 2x30A outlets. How else would I bring these 2x30A outlets without two sets?

If you have a solution as to re-combine those 2x30A outlets into one 60A circuit, then I'm all for upgrading my wires to 6AWG. They're still in their shrinkwrapped spools.

said by peterboro:

I'm sure you covered this in previous threads but I can run a natural gas furnace and fridge with a 1200W. This isn't a theoretical premise as I have used the gen several times during power outages with both and didn't have to keep the fan on.

Sounds a bit extreme, then again I don't know the size of your appliances. Yes theorically both can run on 1200W as long as the generator has another 500W-1000W peak wattage.

But then you have space for nothing else

Reason I'd leave the furnace fan on is to give myself even more power usage room and create less surge watt demand on the generator. A generator prefers a steady demand vs. many surges.

said by jack b:

Why don't you design it for 240 volts to start with: go with 2 hots a neutral and ground?

You're unnecessarily limiting yourself with a 120 volt circuit. I'd run 4#10 conductors and 30 amp L14-30p plug connectors. If you only want 120 volt only use 3 conductors for now.

If you're planning on attempting pulling or pushing those cables in pvc, don't go under 1-1/2 inch diameter.

And do yourself a favor and don't backfill the trench until after the wire is run in the pipe.

Because of generator capacity. If I was to run 2 hots, 1 neutral 1 ground, guess what, I'd be limited to 30A total on 120v/240v.

Generators over 6000W with 240v have two outlets.
1x 120V 30A
1x 120/240 30A

I want 60A, I don't care for 240V.

Why no 240V? Again, only dryer and stove use 240V. And within a year or two, our stove will be natural gas.

I could run a 7th wire in there to support 240v on one of the wire sets, and ya I'm thinking of 1 1/2" inch now.


macsierra8
Baby Newfoundland
Premium
join:2003-11-30
Minden, NV
reply to alkizmo

For a number of reasons I put my generator on a small trailer. I think mobility is a big plus for a generator. In the past, a permanent mount generator always bit me in the ass one way or the other..



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting

1 recommendation

reply to alkizmo

I think a lot is getting lost in translation here. You can pull multiple circuits through the same conduit, as long as you de-rate properly. "Paralleling" conductors is using two or more smaller conductors to make up one bigger conductor. This is only allowed with 1/0 and larger conductors.

I would *highly* suggest that you at least consult a licensed electrician to help you before you close up your trench or start pulling wire.
It sounds like some of the code issues are confusing you. Your wiring plans are getting "creative" and not making much sense. Your plans are getting way more complicated than they need to be.

Pay someone who knows what they are doing for an hour of their time to come out and explain what needs to be done. It will save you a lot of headache.
--
I just might be the most "licensed" S.O.B. you know.



mackey
Premium
join:2007-08-20
kudos:12
reply to alkizmo

said by alkizmo:

said by jack b:

Why don't you design it for 240 volts to start with: go with 2 hots a neutral and ground?

You're unnecessarily limiting yourself with a 120 volt circuit. I'd run 4#10 conductors and 30 amp L14-30p plug connectors. If you only want 120 volt only use 3 conductors for now.

Because of generator capacity. If I was to run 2 hots, 1 neutral 1 ground, guess what, I'd be limited to 30A total on 120v/240v.

Generators over 6000W with 240v have two outlets.
1x 120V 30A
1x 120/240 30A

I want 60A, I don't care for 240V.

Um, you can pull 60A @120v out of that 30A 120/240 outlet if it's split up. While it's only 30A at 240v, when you split it to 120v with a neutral each hot leg can then provide 30A so it's really 2x 30A. This gives you your 60A while only using 4 wires (2x hot, 1 neutral, 1 ground) instead of 6.

/M

peterboro
Avatars are for posers
Premium
join:2006-11-03
Peterborough, ON
reply to alkizmo

said by alkizmo:

Sounds a bit extreme, then again I don't know the size of your appliances. Yes theorically both can run on 1200W as long as the generator has another 500W-1000W peak wattage.

It's rated Output.•1200W Surge: Max AC output: 1000W but I think like our beer Canadian watts are probably stronger than their American counterparts.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to nunya

said by nunya:

I think a lot is getting lost in translation here. You can pull multiple circuits through the same conduit, as long as you de-rate properly. "Paralleling" conductors is using two or more smaller conductors to make up one bigger conductor. This is only allowed with 1/0 and larger conductors.

Ah this is where you and I lost each others.

I'm not paralleling conductors. My two sets of H/N/G would each be on their own circuits from the generator.

I'm adapting my raceway setup to accommodate what is the most likely generator I'd buy if I were to upgrade.

The answer to that is a typical portable generator (gas or diesel) that has two twist lock outlets, each 30A, each a circuit.

Thus I'd have two circuits in my raceway. And I have de-rated properly in a previous topic
»Re: NMWU cable protection for direct burial - Suggestions?

Now you'll say "But that shows 10 gauge de-rates to 24A" which is right. I'm debating myself whether to upgrade to 8 AWG to support 36A, then again 30A each circuit is only peak wattage support when the generator would probably hang around 25A maximal constant output per outlet . That's a side issue which I take seriously (whether to go 8AWG).

said by nunya:

I would *highly* suggest that you at least consult a licensed electrician to help you before you close up your trench or start pulling wire.
It sounds like some of the code issues are confusing you. Your wiring plans are getting "creative" and not making much sense. Your plans are getting way more complicated than they need to be.

Pay someone who knows what they are doing for an hour of their time to come out and explain what needs to be done. It will save you a lot of headache.

I've spent countless hours reading and writing back and forth with you and Whizkid. No random electrician will fix my confusion.

There's no confusion.

1 - 3000W genny
2 - 10AWG RW90 in properly sized raceway
3 - Transfer switch with bonded neutral
4 - Ground from transfer switch to house panel

Now because I've placed some extra stuff in the raceway for upgrade-proofing, everything is thrown out of the window? The trench cost me 75$ and muscle aches. An electrician will cost me 200$ for the visit and guess what, I highly doubt what he'll tell me will be doable for me.

My wife works with hydroelectric engineers, but I'm afraid to call in a favor from them and end up turning my 1000$ project into 50,000$ (Well that's how THEY work, well, isn't how all electrician work?).

If my plan doesn't allow to bring in a 2nd circuit if I upgrade my generator, then too bad, I'll be stuck at 3000W which is better than none.

Sorry if I seem a bit irritated. I've already tripled my budget, and I don't see it being ever completed unless I put a stop to "more".

said by mackey:

Um, you can pull 60A @120v out of that 30A 120/240 outlet if it's split up. While it's only 30A at 240v, when you split it to 120v with a neutral each hot leg can then provide 30A so it's really 2x 30A. This gives you your 60A while only using 4 wires (2x hot, 1 neutral, 1 ground) instead of 6.

No it's not. If the 2-pole breaker is rated 30A, it's 30A total, not each pole. Maybe SOME portable generators output 60A on their 120/240 sockets, but I have to upgrade-proof for the most likely scenario and within a budget.


mackey
Premium
join:2007-08-20
kudos:12

1 edit

said by alkizmo:

said by mackey:

Um, you can pull 60A @120v out of that 30A 120/240 outlet if it's split up. While it's only 30A at 240v, when you split it to 120v with a neutral each hot leg can then provide 30A so it's really 2x 30A. This gives you your 60A while only using 4 wires (2x hot, 1 neutral, 1 ground) instead of 6.

No it's not. If the 2-pole breaker is rated 30A, it's 30A total, not each pole. Maybe SOME portable generators output 60A on their 120/240 sockets, but I have to upgrade-proof for the most likely scenario and within a budget.

You don't understand how 120/240 circuits work. When using a 2-pole breaker that provides 240v between the polls but also has a neutral, then it IS 30A on each pole!

120/240 circuits have 3 wires - 2 hots and a neutral. When you are using a single 240v load, say 30A, each hot wire will be carrying 30A and the neutral will have nothing (0A). If you had a single 30A 120v load then one hot will have 30A, the neutral will have 30A, but the 2nd hot will have nothing on it! When you have 2 30A loads, each one between a hot and the neutral, one hot leg will have 30A, the other hot leg will also have 30A, but the neutral will again have nothing (0A)! The generator will see this as a single 240v load at 30A.

Edit: oh yeah, if you have one 15A 120v load between one hot and the neutral and a 30A 120v load between the other hot and the neutral, one hot will have 15A, the other will have 30A, and the neutral will also have 15A.

So yes, you will have 60A @ 120v when taken out of a 30A 120/240v socket. This is considered a single circuit and as it only needs 3 wires you can use the 3-wire derating table.

/M


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by mackey:

You don't understand how 120/240 circuits work.

No I do, but some generators limit the 120/240 outlet to 30A no matter what.

God damnit it's hard to plan your wiring when you don't know what generator you'll be supporting in the future.

I may as well throw in 6AWG 3-wire + ground and cross my fingers. At least I won't be violating some sort of code by having two sets of wires in one conduit.


mackey
Premium
join:2007-08-20
kudos:12

said by alkizmo:

said by mackey:

You don't understand how 120/240 circuits work.

No I do, but some generators limit the 120/240 outlet to 30A no matter what.

And even though you get 60A "usable" with 120v devices, the generator will see it as a 30A 240v load. You're basically wiring the 2x 30A 120v loads in series to get a single 30A 240v load.

/M

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus
reply to alkizmo

said by alkizmo:

said by mackey:

You don't understand how 120/240 circuits work.

No I do, but some generators limit the 120/240 outlet to 30A no matter what.

Right, the generator will limit BOTH hot wires to 30A at the same time. It won't be a total of 30A from both legs, generator windings don't work that way. You can have 30A coming 'from' one leg, through the load, and back up 'to' the other leg. The generator is supplying 30A (at 240 volts). But, since it also has a neutral you could power TWO 120 volt loads at 30A each -- a total of 60A at 120 volts.

Please pull four wires, H-H-N-G and leave it at that. Use a large enough conduit to make pulling easy, it will help your back recover from the digging.

As for the genny providing two 30A outlets, they're almost certainly in parallel with each other and not derived from separate windings, so the total available current can be supplied to one outlet. They put two there for convenience.

Finally, even though at this point you don't think you'll want to power a 240 volt load, why not allow for it? The four wire feed will do just that and allow you to wire that new panel the way it was intended.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by garys_2k:

Finally, even though at this point you don't think you'll want to power a 240 volt load, why not allow for it? The four wire feed will do just that and allow you to wire that new panel the way it was intended.

Well originally it seemed too complicated to get 240V and 120V at full 60A when I originally believed it was 30A MAX on the 120V side.

Now it seems easier to bring in H/H/N/G then two sets of H/N/G

Question, this is an extract from the CEC section regarding raceways for 3 conductors.

quote:
††For 3-wire 120/240 V and 120/208 V service conductors for single dwellings, or for feeder conductors
supplying single dwelling units of row housing of apartment and similar buildings, and sized in accordance
with Rules 8-200(1), 8-200(2), and 8-202(1), the allowable ampacity for sizes No. 6 and No. 2/0 AWG shall
be 60 A and 200 A, respectively. In this case, the 5% adjustment of Rule 8-106(1) cannot be applied
I'm guessing 6 AWG for H/H/N/G for 30amps on each leg?

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

I have no idea what's contained in "Rules 8-200(1), 8-200(2), and 8-202(1)," and what implications the distance you're running the feeds may be, so I can't help you there. But as to your comment "...when I originally believed it was 30A MAX on the 120V side," it IS 30 A max on BOTH 120 volt legs. You have two legs each supplying 30 A independently, a total of 2 X 30 = 60 A for your 120 volt circuits.

Your new panel can contain a main 30 A two pole breaker (again, 2 X 30) and, if you balance your loads properly, you could pull a total of 60 A of 120 volt current. If you ever DO run a 240 volt circuit it will be limited to 30 A (and, of course, the TOTAL current on either/both branches can't exceed 30 A from all the loads, 120 and 240 volt combined), but running, say, a small well pump that is fed from a 240 volt 15 A circuit should be alright if the inrush isn't too bad.



mackey
Premium
join:2007-08-20
kudos:12
reply to alkizmo

#6 would be overkill but work just fine. Since there will only be 3 current-carrying wires #10 is all you need (since no single wire will have more then 30A on it) unless something else requires it to be derated. Personally I'd bump it up to #8 anyway, but as long as the conduit is big enough you can always replace the wire later if needed.

/M


JTY

join:2004-05-29
Ellensburg, WA
reply to alkizmo

I'd suggest going with 1 1/4" conduit. It's not much more expensive, and will make cable pulling much easier, allow for easier changes if needed, and be somewhat stronger.

Outlet wise, you should be able to find generators in the 5000watt range that have a single 240V outlet. I know my dad's Honda 5500Watt did.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mackey

said by garys_2k:

I have no idea what's contained in "Rules 8-200(1), 8-200(2), and 8-202(1)," and what implications the distance you're running the feeds may be, so I can't help you there.

Irrelevant rules about wattage requirements to feed dwellings of X size.

Here's just so you can rest assured:

quote:
8-200 Single dwellings (see Appendix B)
(1) The minimum ampacity of service or feeder conductors supplying a single dwelling shall be based on the
greater of Item (a) or (b):
(a) (i) a basic load of 5000 W for the first 90 m2 of living area (see Rule 8-110); plus
(ii) an additional 1000 W for each 90 m2 or portion thereof in excess of 90 m2; plus
(iii) any electric space-heating loads provided for with demand factors as permitted in Section 62
plus any air-conditioning loads with a demand factor of 100%, subject to Rule 8-106(4); plus
(iv) any electric range load provided for as follows: 6000 W for a single range plus 40% of any
amount by which the rating of the range exceeds 12 kW; plus
(v) any electric tankless water heaters or electric water heaters for steamers, swimming pools, hot
tubs, or spas with a demand factor of 100%; plus
(vi) any loads provided for in addition to those outlined in Items (i) to (v) at 25% of the rating of
each load with a rating in excess of 1500 W if an electric range has been provided for, or 100%
of the rating of each load with a rating in excess of 1500 W up to a total of 6000 W, plus 25%
of the load in excess of 6000 W if an electric range has not been provided for; or
(b) (i) 100 A where the floor area, exclusive of basement floor area, is 80 m2 or more; or
(ii) 60 A where the floor area, exclusive of basement floor area, is less than 80 m2.
(2) The minimum ampacity of service or feeder conductors from a main service supplying two or more
dwelling units of row-housing shall be based on
(a) Subrule (1), excluding any electric space-heating loads and any air-conditioning loads, with
application of demand factors to the loads as required by Rule 8-202(3)(a)(i) to (v); plus
(b) the requirements of Rule 8-202(3)(b), (c), and (d).
quote:
8-202 Apartment and similar buildings (see Appendix B)
(1) The minimum ampacity of service or feeder conductors from a main service supplying loads in dwelling
units shall be the greater of Item (a) or (b):
(a) (i) a basic load of 3500 W for the first 45 m2 of living area (see Rule 8-110); plus
(ii) an additional 1500 W for the second 45 m2 or portion thereof; plus
(iii) an additional 1000 W for each additional 90 m2 or portion thereof in excess of the initial 90 m2;
plus
(iv) any electric space-heating loads provided for with demand factors as permitted in Section 62
plus any air-conditioning loads with a demand factor of 100%, subject to Rule 8-106(4); plus
(v) any electric range load provided for as follows: 6000 W for a single range plus 40% of any
amount by which the rating of the range exceeds 12 kW; plus
(vi) any loads provided for, in addition to those outlined in Items (i) to (v), at
(A) 25% of the rating of each load with a rating in excess of 1500 W, if an electric range has
been provided for; or
(B) 25% of the rating of each load with a rating in excess of 1500 W plus 6000 W, if an
electric range has not been provided for; or
(b) 60 A.
As for the rest of your post.. yes ya I think I'm just failing to explain that I understand how generator feed works on the 120V/240V line

said by mackey:

#6 would be overkill but work just fine. Since there will only be 3 current-carrying wires #10 is all you need (since no single wire will have more then 30A on it) unless something else requires it to be derated. Personally I'd bump it up to #8 anyway, but as long as the conduit is big enough you can always replace the wire later if needed.

But since I'd have two hot legs at 30A each, wouldn't the neutral return be taking on both 30A, hence 60A?

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
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said by alkizmo:

As for the rest of your post.. yes ya I think I'm just failing to explain that I understand how generator feed works on the 120V/240V line

said by mackey:

#6 would be overkill but work just fine. Since there will only be 3 current-carrying wires #10 is all you need (since no single wire will have more then 30A on it) unless something else requires it to be derated. Personally I'd bump it up to #8 anyway, but as long as the conduit is big enough you can always replace the wire later if needed.

But since I'd have two hot legs at 30A each, wouldn't the neutral return be taking on both 30A, hence 60A?

No. The two 30A feeds are out of phase with each other, so the neutral will only carry a current representing the difference between what is fed to each phase.

For example, feed 20 A on phase X and 0 A on phase Y and the neutral carries 20 A. Feed 20 on X and 15 on Y and the neutral carries 5. Feed 15 on X and 15 on Y and the neutral carries zero.

So, your neutral never has to be larger than the hots. If you balance your loads well on the circuit board it may carry very little current (but still has to be rated to carry the full 30A if you have a very unbalanced load).

This is the tricky stuff about AC. Things don't always add up as simply as they would seem to.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

Ok so for my 60A, I can go 8 gauge on all conductors... as long as I use 2 hots.

Woah....

Ya gonna return most of my stuff (PVC, cables) tomorrow and get myself some 8AWG + 1 1/2 PVC.

And ya, that supporting 240V is a lot simpler to bring in 60A of 120V.

thanks mate!