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alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo to Killa200

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Re: Generator house link project - The progress.

said by Killa200:

I didn't change my mind, i'm talking about two different sides of the romex,

The seperate ground bar in the sub panel (your transfer switch) gets the ground ONLY from that romex. On the other end of the romex, that goes to your main panel, the ground AND neutral goes to your common bar at the bottom.

That is how you get an electrode ground to your generator, and your chassis of the transfer switch,

Ah you just misunderstood me.

The romex in question was the one in the picture, the romex that goes from the raceway house entrace to my transfer switch.

Basically that ground is connected to nothing, it only links with the generator H/H/N from the RW90 from the raceway.

But I understand what you meant. When I'm going to be using some more romex to link my panel to the transfer switch, I'll link the ground going from panel to switch, that way the chassis is also grounded.

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3 to Killa200

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said by Killa200:

The neutral bus and ground bus are supposed to be floating from each other and NOT attached, since this is a sub panel.

Incorrect. This is a transfer switch; definitely NOT a sub-panel with a main breaker elsewhere. And the neutral is switched in this transfer switch. When on generator, there would be no neutral-ground bond. In this case, the generator is being operated as a separately derived source.

Problem is, it is also switching the utility neutral to ground. This panel is intended to be placed before the main breaker on the utility side as well. In the OP's case, the panel becomes a sub-panel on utility power; but a main on generator power. It will need some tricky wiring. I will have to look more at it later; have to run to work.

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by whizkid3:

Problem is, it is also switching the utility neutral to ground. This panel is intended to be placed before the main breaker on the utility side as well. In the OP's case, the panel becomes a sub-panel on utility power; but a main on generator power. It will need some tricky wiring. I will have to look more at it later; have to run to work.

The transfer switch was designed to allow using floating neutral OR neutral bonded generators.

Look on the top left side of the diagram, where the utility neutral comes in.
You'll see that it specifies to wire the utility neutral to the bus for unbonded neutral generators. You only connect utility neutral to the switching mechanism if the generator has bonded neutral.

I don't know if that changes things for you?

Killa200
Premium Member
join:2005-12-02
TN

Killa200 to whizkid3

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said by whizkid3:

said by Killa200:

The neutral bus and ground bus are supposed to be floating from each other and NOT attached, since this is a sub panel.

Incorrect. This is a transfer switch; definitely NOT a sub-panel with a main breaker elsewhere. And the neutral is switched in this transfer switch. When on generator, there would be no neutral-ground bond. In this case, the generator is being operated as a separately derived source.

Problem is, it is also switching the utility neutral to ground. This panel is intended to be placed before the main breaker on the utility side as well. In the OP's case, the panel becomes a sub-panel on utility power; but a main on generator power. It will need some tricky wiring. I will have to look more at it later; have to run to work.

Yeah, I see where I am wrong in this case. Guess i am still in the mindset of my own standby genset project, which has a built in throw main so it is sub fed on both sources.

Could he put up a disconnect in the shed as his main disconnect and feed the transfer as a sub on the genset as well to keep it simple on the transfer switch?

fcisler
Premium Member
join:2004-06-14
Riverhead, NY

fcisler to alkizmo

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That orange NM....you sure that's #8? I would wager it's #10....all the #8 or #6 I see has it's sheathing in black.

I would also strip the sheathing back to the strain relief. Having that much in the panel looks sloppy to me.

jack b
Gone Fishing
MVM
join:2000-09-08
Cape Cod

jack b

MVM

He's gonna need more ground exposed, too.

alkizmo
join:2007-06-25
Pierrefonds, QC

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said by Killa200:

Yeah, I see where I am wrong in this case. Guess i am still in the mindset of my own standby genset project, which has a built in throw main so it is sub fed on both sources.

Could he put up a disconnect in the shed as his main disconnect and feed the transfer as a sub on the genset as well to keep it simple on the transfer switch?

I'm not sure what the problem is anymore.

Is it that the transfer switch cuts off neutral from the utility power when switching to generator feed? Because as I said the utility neutral can be tied to the bus bar instead of the breaker. It's a designed option.

If it's the matter of the transfer switch not having a main disconnect (It can only go Generator/Utility but no OFF), then ya, can I just add a main disconnect? Though I'd rather add it next to the transfer switch and not at the shed.
said by fcisler:

That orange NM....you sure that's #8? I would wager it's #10....all the #8 or #6 I see has it's sheathing in black.

Correct, it's 10AWG, made a mistake while marking the photo.
said by fcisler:

I would also strip the sheathing back to the strain relief. Having that much in the panel looks sloppy to me.

I thought it was cleaner with sheathing the wires as further as possible, but if professionals remove the sheath from the strain relief, then I'll do that.
said by jack b:

He's gonna need more ground exposed, too.

You mean the NMD90 ground? Why exposed? Anyway that wire will be tied to the bus.

Side question If I'm supposed to connect the circuits return ground to the bus bars on the sides (as the one on the bottom is only connected to the chassis) then what am I supposed to do? There are only 20 bus slots (10 per side) for 20 possible circuits. Not that I'd have 20 circuits, but still... an academic question

whizkid3
MVM
join:2002-02-21
Queens, NY

1 edit

whizkid3

MVM

OK - lets make it simple.

Originally, you had no transfer switch. The generator was going to provide power to completely seperate circuits that would have no common wiring, other than tying the grounding electrodes together, as is required. Because in this case the generator is a seperately derived source, it had to have the neutral bonded to ground at or near the generator. (Ideally, and code wise between the generator windings and the first disconnect switch downstream.)

Now, you have a manual transfer switch (MTS). Because it has the ability to switch the neutral, you have two choices:

1. Keep the generator as a seperatately derived source as before. Make a ground-neutral bond at or near the generator. Run the neutrals into the switch and switch between the utility power & neutral or the generator power & neutral. This is probably the easiest solution from where you started.

2. Do not have the generator as a separately derived source. This would mean relying on the ground-neutral bond at your utility service (main) disconnect. To do so, requires that you do not switch the neutrals at your MTS. Instead, they would be solidly bonded together at the MTS. This would be done by wiring both the neutral from the upstream utility source and the neutral from the generator directly to the (isolated) neutral bus in the MTS. And you would have no neutral-ground bond at the generator. (FYI - I see the dotted line in the MTS schematic now. Easy to miss that. That is how this option would be done.)

I had to spend some time reviewing it. Sorry, but I could not this morning. In effect, Killa200 was on track by calling it a 'sub-panel'. In reality, it is a combination MTS & sub-panel. Hope this is less confusing. I recommend option 1 above, btw. I wish I had a copy of the 'NEC Handbook' handy. They show wiring diagrams of exactly the situation of both methods above for a residential install. Maybe someone can post them here?
whizkid3

2 edits

whizkid3

MVM

FYI - regarding the grounding... (trying to make this clear).

The ground bar at the bottom of the panel is an equipment ground bar. It is NOT part of the grounding electrode system. In all cases, the only things that get connected to this are:
1. downstream equipment grounds.
2. The feeder ground from the upstream utility panelboard. You MUST run four wires from this board 2H, N & G. The ground may be a metal conduit from the upstream utility panelboard or it can be a separate wire with the other three.
3. A feeder ground from the generator. This MUST come from the point at which the generators neutral-ground bond is made with generators that are separately derived sources like I believe yours is. If your generator will not have an N-G bond, the ground wire still must be run to the generator to provide it with an equipment grounding source.

In your case, you are running a grounding electrode wire from the generator back to the main building grounding electrode system (as is required). This is not to be run to the ground bus in the bottom of the panel. You will need a separate equipment ground wire (or metal conduit) run with your H&N conductors from the point where the generator's N-G bond is made to the ground bus in the bottom of the MTS.

(If you are only wiring one hot in any feeder, pretend you are wiring two hots, when I call it four wires.)

How to do this...

At the metal junction box where (I believe) you are making the generator's neutral-ground box; you will have the following all bonded together:
1. The bare wire that goes to the home's grounding electrode system. Not sure where you are connecting it but we discussed those options already.
2. The feeder equipment ground conductor that runs with the generator power to the small ground bar at the bottom of your MTS. I believe this is your Romex from the junction box to the MTS.
3. The upstream ground connection to the generator. Again, I believe this is your bare wire.
4. A bond to the metal junction box. (Needs to be a bolted lug with no paint under it and not using sheet-metal screws to attach it.)

If you have the generator's N-G bond further upstream (i.e. right at the generator), then you will need to run a separate grounding electrode wire and feeder equipment grounding wire. The bare wire can run direct from the generator's N-G bond to the grounding electrode system in the home; but you will still need an 'equipment grounding wire' for the generator power feeder run from the generator's N-G bond, with the generator's power wires, to the ground bus in the MTS.

Two more things:

1. Downstream equipment coming from the breakers in the MTS, get their white neutrals wired to the two vertical (isolated) neutral buses on either side of your panel. Their ground wires go to the small bus at the bottom, that is bonded to the MTS' metal enclosure.

2. Stop posting very wide photos!

Killa200
Premium Member
join:2005-12-02
TN

1 recommendation

Killa200 to alkizmo

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to alkizmo
Glad to see I wasn't too far off base with things,

Whizkid, when are you going to open up a school for this stuff on the forums? lol

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

Click for full size
Click for full size
A picture tells 1000 words. Here are two (courtesy of alkizmo, with my annotations). Enjoy

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

Thanks to Whizkid's advices and him completing my diagrams (Wasn't complete or perfect) I made the decision to go with option 1.

Otherwise I'd have had to pull out all 60 feet of continuous bare from inside my basement ceiling and put it back inside all the PVC raceway and back in the ceiling and I'd rather not

So I'll buy a roll of 10AWG RW90 green and do the separate derived system. Plus half that roll will be used for the 2nd PVC raceway that brings power to the shed. All wires in it were 10AWG except for the ground, which would have been 12AWG. I'd have kept that circuit on 15A, but now I could do 30A

Just gotta bond the neutral inside the generator.
alkizmo

alkizmo

Member

So I'm going to be putting the final touches to the setup and closing everything up after.

Question: While I cannot use Great Stuff to seal the inside of the PVC raceway at the entrance point to the house, can I put it outside the PVC to seal any cracks between the PVC and the exterior wall?

Killa200
Premium Member
join:2005-12-02
TN

Killa200

Premium Member

said by alkizmo:

While I cannot use Great Stuff to seal the inside of the PVC raceway at the entrance point to the house, can I put it outside the PVC to seal any cracks between the PVC and the exterior wall?

That is fine.

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3 to alkizmo

MVM

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You also need to seal the inside of the conduit where it enters the house to prevent cold air from coming in; heat loss; and t condensation from forming inside. (This is a code requirements, and simply common sense.) Use some duct seal available at HD or virtually anywhere outside the supermarket. Merry Christmas!

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by whizkid3:

You also need to seal the inside of the conduit where it enters the house to prevent cold air from coming in; heat loss; and t condensation from forming inside. (This is a code requirements, and simply common sense.) Use some duct seal available at HD or virtually anywhere outside the supermarket. Merry Christmas!

Yeah that I understood when you told me "great stuff" was not in the code

But for the outside of the pipe, I really wanted to make a good seal and it wouldn't have been easy with normal tubed stuff. There's about 16 inches of depth between the exterior wall and the wooden beam from inside. And in between the two, there is a small gap (for air flow behind my brick wall outside). So I really hoped Great Stuff would be allowed as it's ideal for the situation....

and it is allowed

For the inside of the pipe I'll use duct seal, but I'm not sure whether that or simple silicone would suffice? I'm not sure which one is easiest to remove when/if I want to pass through more wires.

jack b
Gone Fishing
MVM
join:2000-09-08
Cape Cod

jack b

MVM

Silicone sets up and adheres to everything, avoid if possible.

Use duct-seal if you can find some, it stays pliable. It's kind of like the plasticine clay everyone played with in elementary school!

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by jack b:

Use duct-seal if you can find some, it stays pliable. It's kind of like the plasticine clay everyone played with in elementary school!

Ok so it doesn't really dry? Cause that would be ideal to remove later.

Goodie.

Alright dudes and sparkies. I'm gonna be wrapping up gifts (not for you, sorry) and then gone for the day for the family Christmas party.

Chat to ya all tomorrow as I plan to run the last few wires (green ground RW90 in the raceway especially) and if I get the chance, even hook up the transfer switch to the electrical panel

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3 to alkizmo

MVM

to alkizmo
Duct seal inside the conduit (or you could buy a better, harder to find and more expensive solution like the professionals use on commercial projects - not likely).

Great Stuff is fine in the wall on the outside of the conduit around it.

For sealing the exterior where the conduit penetrates the wall, I use silicone cauking.

Merry Christmas!

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

Ok so I just finished passing the last wire in the raceway (green ground) and bonding neutral to ground.

I had to do the bond from within the male plug to the generator.

When I tried to open the generator panel to bond from inside, it was a major "locked in" piece of work. Everything was sealed within another box and I didn't want to have to dismantle the whole thing just to bond and maybe one day unbond.

So I modded the plug to run a piece of 10AWG wire between neutral and ground. It's all done very neatly, as the bonding conductor would enter into each hole for neutral and ground.

As for grounding the generator chassis to the bare copper, that's will need some extra basic parts when the hardware stores open again.

The bolt on the panel for attaching my grounding cable doesn't seem designed for running a cable around it. I'm thinking that a split nut or grounding bolt could do it.

God working in below freezing temps makes it hard and painful work

Not only are the wires un-cooperative, but you can't use gloves to do the fine work and the fingers freeze and become also un-cooperative.

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

said by alkizmo:

The bolt on the panel for attaching my grounding cable doesn't seem designed for running a cable around it. I'm thinking that a split nut or grounding bolt could do it.

Use a split-bolt; or just run it into an unused screw terminal on the ground bus.

You are using a #6 bare, stranded ground wire, correct? If so, you can not simply run it under the head of a screw. You need a lug or other approved terminal.

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by whizkid3:

You are using a #6 bare, stranded ground wire, correct? If so, you can not simply run it under the head of a screw. You need a lug or other approved terminal.

Correct, #6 stranded bare copper.

I'll go buy a split bolt large enough to accommodate the bolt on the generator.

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

Oh, this is for the generator side? (I had though it was at the electrical panel). Yeah, use a lug.

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

said by whizkid3:

Oh, this is for the generator side? (I had though it was at the electrical panel). Yeah, use a lug.

Yeah the generator side. The ground point on the generator is a bolt, bolt's too short to squeeze in the 6AWG between two washers.

That ground cable on the house side will terminate on the electrical panel's ground bus (gotta find a bit enough hole).

edit - Or I might just use a split bolt or two to tie that 6AWG to the house electrode conductor (another bare copper 6AWG).
alkizmo

3 edits

alkizmo

Member

Ok the wife and kid went out for a couple of hours so I took the opportunity to cut power and do the circuit transfer to the transfer switch.



I'll go back to home depot to buy a few knockout covers (a few holes that seemed good at the time but weren't).

Also missing 2 more circuits, but they aren't critical (more for convenience). Those can wait.

Orange NMD90 from under is the main electrical panel feed. It's on a couple of 20A fuses, didn't have 30A on hand. Hope this will last a day

I realize now that I should have pulled it more to the side as right now it's blocking the left column for breakers. I'll just pull in a bit more cable and make it curve further to the left.

The ground from that NMD90 goes to the ground bus in the transfer switch and the ground bus in the main panel. No bond in the transfer switch.

Orange NMD90 from top is the generator feed. The ground goes under the breakers but there's plenty of space and no metal part to make contact with by mistake.

God, only 2 feeds and 3 circuits and the thing is messy.

Note - Those who are attentive to details will notice a capped red wire. It was the 3-wire romex feeding the kitchen. I didn't think it would come like that, so I didn't have an extra breaker on hand.
Considering that Leg1 is for microwave outlet and lights, and Leg2 is for the outlets around the counter, should I still put those 2 circuits on a 2-pole breaker? Or can they be on different breakers? (as long as they are on different legs of course).

Question: One of the circuits I transfered didn't have enough jacket to extend to the stress-relief. See the picture below.



Can I electric tape it?

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

said by alkizmo See Profile
God, only 2 feeds and 3 circuits and the thing is messy.

Question: One of the circuits I transfered didn't have enough jacket to extend to the stress-relief. See the picture below.
Can I electric tape it?

[/BQUOTE :

I agree with you it is very messy. What's with the bare ground coming from the top left down behind the breakers to the ground bar at the bottom? In fairness though it does take some time and experience.

I would just install a junction box and make a splice connection for the circuit that the jacket is short.


whizkid3
MVM
join:2002-02-21
Queens, NY

1 edit

whizkid3 to alkizmo

MVM

to alkizmo

wiring horror show
You had a good handle on everything until now.

Wires & cables that are two short or pulled taught or not routed properly within the box are unacceptable. If the cables are too short, use a box to splice them to a cable that is long enough. The wires should travel around the inside of the box in the wiring gutters (space to the left and right of the enclosure). They should have smooth bends and travel at right angles to the box. In other words, enter the box, go all the way to the left or right, then down and turn into their terminals at right angles (be they breakers, buses, etc).

Cable jackets should just be visible on the inside of the box at every cable connector. If not, its too short.

The ground wire that is nearly touching the neutral bus terminal is unacceptable. The hot & neutrals that travel behind the bar that connects the two neutral buses is unacceptable.

All cables have to be secured & supported (external to the box) within 12" maximum of where they enter the box. In other words, staples.

Clean it up and make us proud.

alkizmo
join:2007-06-25
Pierrefonds, QC

alkizmo

Member

Considering your extreme perfection requirement, I believe the previous owner of this house had a lazy joe-slobavich of a "master" electrician.

From top to bottom of your "commented" image:

Why is there a marrette?
Because the "master" electrician that serviced that box tied all grounds together at the top of the electrical box and then ran a bigger gauge bare copper down to the ground bus.

When I pulled out some circuits, I basically had to snip off the ground wire from that twisted pile of copper, which left is very short.

Why is there unjacketed wiring? The main electrical panel is not designed to save wiring inches. Neutral bus can be as far as 2 feet below where the hot connects. If you're telling me I need to make a junction box to gain 6 inches of jacketing, instead of electric tape... I'll do it, but I'll hate you The cable isn't that tight.

Why is there a second bare copper ground that "apparently" comes out of the orange NMD90? Optical illusion. There's a second knockout hole right behind the NMD90. I just made the mistake of trimming the jacket a bit too short from the inside of the box.

I'll try to do the right-angle thing. A bit unpleasant to be so strict. Zip-ties okay to force such angles?

Neutral bar is actually just as far UP above the back plate than the side buses are from the edges....but anyway as I said, it's too tight to add breakers on the left, so I'll pull it a bit more inside to make those right angle turns you like so much, Mein Sparky!

Staples to hold cables every 12 inches? How do people accomplish that when they fish-tape wire?
And I'm not going to retroactively apply code to all the old circuits I just transferred.... That would be.. insane? You should see the horror show in my main electrical panel....As I said, return grounds twisted all together to a bigger gauge ground to the ground bus. And one of those bigger gauge ground is actually screwed to a screw that was used to MOUNT the panel?!?!

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

said by alkizmo:

Considering your extreme perfection requirement

Definitely not. Electrical work is not equal to constructing, let's say, a piano. Just basic workmanship standards (which, btw, is a code requirement).
said by alkizmo:

When I pulled out some circuits, I basically had to snip off the ground wire from that twisted pile of copper, which left is very short.

Need to fix it, by splicing in a new wire in a junction box.
said by alkizmo:

Why is there unjacketed wiring? If you're telling me I need to make a junction box to gain 6 inches of jacketing, instead of electric tape...

Yes.
said by alkizmo:

If I'll try to do the right-angle thing. A bit unpleasant to be so strict. Zip-ties okay to force such angles?

There should be enough cable to make right angles. Zip ties are OK, but not for that purpose. Electrical wiring in zip-ties should be relatively loose. Pulling a plastic zip tie into the insulation of a wire to pull it in the direction you want, will only damage the insulation. Plus, the wire needs to 'breath', to dissipate heat.
said by alkizmo:

Staples to hold cables every 12 inches?

I didn't say that. I said within 12" maximum from any box. (Staples or some other approved strap.)
said by alkizmo:

How do people accomplish that when they fish-tape wire?

They don't. The code doesn't require securing fished wires. And you are not fishing wires.
said by alkizmo:

And I'm not going to retroactively apply code to all the old circuits I just transferred.... That would be.. insane? You should see the horror show in my main electrical panel....As I said, return grounds twisted all together to a bigger gauge ground to the ground bus. And one of those bigger gauge ground is actually screwed to a screw that was used to MOUNT the panel?

(That last one should be fixed.)
KirkyInCT
join:2008-11-04
Higganum, CT

KirkyInCT to alkizmo

Member

to alkizmo
said by alkizmo:

And I'm not going to retroactively apply code to all the old circuits I just transferred.... That would be.. insane? You should see the horror show in my main electrical panel....As I said, return grounds twisted all together to a bigger gauge ground to the ground bus. And one of those bigger gauge ground is actually screwed to a screw that was used to MOUNT the panel?!?!

I would fix anything and everything that's not current code ASAP. If you think it's a horror show, it might be even worse than it looks. I'm in a three year old house and went through the electrical fixing all sorts of shortcuts, this was licensed and inspected work, never mind a weekend warrior DIY commando.