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Mr Matt

join:2008-01-29
Eustis, FL
kudos:1
Reviews:
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Correct cable to run through conduit.

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Panel cover open showing generator breaker location
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Panel shown with hub circled
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Panel specification label
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Proposed location of conduit
I have attached pictures of my service entrance above. I have decided to install a 50 Amp generator inlet on my back porch. I already have a 50 Amp Breaker and interlock. I plan on installing a hub at the top of the service panel where there is now a blank plate and running a conduit from the hub through the soffit into the attic.

What would be the correct type of cable to run through the conduit across the attic and then down through another piece of conduit to the generator inlet. I recall a post by kherr regarding some code violation issues because of the way he ran a cable from his generator inlet to his service panel through conduit. I would like to avoid the same problem. One of the sales persons at Lowes recommended to install a cable that consists of 3 #6 Copper conductors and 1 #8 Copper conductor for the 50 Amp inlet but was unable to advise about running the cable though conduit. The total run will be about 70 Feet. I was also wondering what wire gauge and type cable I should use if I want to install a 100 Amp circuit instead of a 50 Amp circuit.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
said by Mr Matt:

I was also wondering what wire gauge and type cable I should use if I want to install a 100 Amp circuit instead of a 50 Amp circuit.

I'll just comment on this part.

You dont want to be pulling #3 (for 100AWG) through conduit.
Jeezus Hard Christ it is!

Also, I don't see #3 fitting in a 50A generator inlet

Mr Matt

join:2008-01-29
Eustis, FL
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According to the panel specification label I can install up to a 2 1/2 inch hub and conduit. I did not plan on running conduit across the attic but 4 Conductor jacketed cable. I was inquiring the correct type of cable to use. The conduit would only be to protect the cable until it passed through the soffit panel. If I ran a 100 Amp Circuit I would terminate the cable at the back porch in a small 100 Amp rain tight panel and install the 50 Amp breaker there and wire the inlet off that panel with #6 gauge conductors.


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to Mr Matt
Install a 2-1/2" conduit then.

kherr
Premium
join:2000-09-04
Collinsville, IL
He wants to know what size CABLE to run for a 100 A sub panel .....


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
said by kherr:

He wants to know what size CABLE to run for a 100 A sub panel .....

And I said 3AWG.

Mr Matt

join:2008-01-29
Eustis, FL
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Reviews:
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reply to kherr
I appreciate your help. I spent about an hour looking for the specifications on jacketed 4 Conductor so I can figure out what type by letter code I should purchase. There are so many letter codes for cable and wire I need help determining the letter codes for the cable which would meet the electrical code for my application. The devil is in the details.

kherr
Premium
join:2000-09-04
Collinsville, IL
Reviews:
·Charter
reply to alkizmo
I didn't see your post, sorry

Getting too involved in watching the Rams lose a game they could win for once ........ They're killing themselves with penalties


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to Mr Matt
said by Mr Matt:

I appreciate your help. I spent about an hour looking for the specifications on jacketed 4 Conductor so I can figure out what type by letter code I should purchase. There are so many letter codes for cable and wire I need help determining the letter codes for the cable which would meet the electrical code for my application. The devil is in the details.

Let Nunya and Whizkid give advices on that.

Though NMD90 isn't going to be recommended for conduit.
TW90 or RW90 would be best, but I dont know how those are "viewed" when not in conduit (in the attic).

Plus, the attic... super hot ambient temperature in there! So many factors involved!

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
reply to Mr Matt
I'd think that having the conduit enter from the bottom of the outdoor panel would help to forever keep rain intrusion to a minimum. Drop down to the right of it and put in two 90 degree swept ends. Pulling will be harder but once it's done it's done for good. Keeping that box dry with a top entry will be an ongoing, forever task.


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8

1 edit
reply to Mr Matt
You can run SE or SER through the conduit since the conduit is used for "mechanical protection". Strip the jacket off on the portion that goes in the conduit (if that is even an issue in your locale). Don't forget to put a bell end on both ends of the conduit in the attic to avoid damaging the insulation of the cable.

The cable should be run under the insulation attic to protect it from the heat and the necessity of derating the conductors, which is necessary if the ambient temp in the installation area is above 86 degrees.
--
The most powerful weapon in the world is ignorance. Politicians exploit it to achieve almost anything they want.



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to garys_2k
said by garys_2k:

Keeping that box dry with a top entry will be an ongoing, forever task.

Using a rated and listed hub solves that problem...


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to alkizmo
said by alkizmo:

And I said 3AWG.

This is in error. The proper size is 1 AWG CU.

You looked in the wrong column...


nunya
LXI 483
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join:2000-12-23
O Fallon, MO
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I guess you are using an ECSBPK05?
You would use 6/3 for a 50A circuit, with the caveat that you need to check for voltage drop problems (probably not an issue). You shouldn't use NM cable in outdoor conduit. Use UF cable or individual conductors.
--
If someone refers to herself / himself as a "guru", they probably aren't.


alkizmo

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

1 edit
reply to John Galt
said by John Galt:

You looked in the wrong column...

Not arguing, just curious for my own education: Which table & column should I be looking at for this situation?

I'm looking at Table B.310.15(B)(2)(1) over the 90C rating (copper).
But I admit that table wouldn't apply once it's in the attic.

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
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reply to John Galt
said by John Galt:

said by garys_2k:

Keeping that box dry with a top entry will be an ongoing, forever task.

Using a rated and listed hub solves that problem...

You're right, I know. It would just bother me, I'd keep looking for rust or other evidence of water intrusion.

Mr Matt

join:2008-01-29
Eustis, FL
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reply to nunya
nunya, you are correct I have a Siemens ECSBPK05 interlock and a 50 Amp two pole circuit breaker which I have yet to install. I am trying to determine the cost of 6/3 UF with ground in 100 Foot lengths. During my search for UF I found a lot of 50 Amp extension cords from 15 feet to 100 feet long in the Recreational Vehicle section of Amazon.com. The plug and receptacle are the same as a 50 Amp Electric Range cord set. I saw a picture of a 50 Amp inlet using the same kind of plug but I have not been able to find a surface mount weather resistant version. I might decide to install the inlet next to the service entrance panel and use a 50 Amp extension cord to connect the service panel to the 50 Amp receptacle on the generator. I appreciate your advice.


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to alkizmo
said by alkizmo:

Not arguing, just curious for my own education: Which table & column should I be looking at for this situation?

I'm looking at Table B.310.15(B)(2)(1) over the 90C rating (copper).
But I admit that table wouldn't apply once it's in the attic.

The termination temp needs to be taken into account.

Generally speaking, all ampacities for "NM-type-ish" cables should be done from the 60 degree column.
--
The most powerful weapon in the world is ignorance. Politicians exploit it to achieve almost anything they want.