Conduit sizing question

[sparky 1971]

The next home inspector I meet who knows anything about electrical beyond checking GFCIs and grounds will be the first one.

You are correct. But the buyers think home inspectors know it all. It's sometimes easier to fix things and get it over with than risk losing a sale. I couldn't begin to guess how many repairs I have made for "double tapped" breakers. A lot of those were Square D and it's ok.

 

[TRWham]

You are correct. But the buyers think home inspectors know it all. It's sometimes easier to fix things and get it over with than risk losing a sale. I couldn't begin to guess how many repairs I have made for "double tapped" breakers. A lot of those were Square D and it's ok.

I do agree one should pick battles carefully.

 

[sparky 1971]

- Is there an advantage of using CU ser (1-1-1-3)?
- Can I attach SER to the bottoms of joists?
- Can SER be bent on its thinner side (but respect the 5X bend radius)?

Also I’m guessing 2/0 SER AL is much bigger than #1 CU and harder to struggle?

2/0 al isn't that bad to work with. Getting it into your main panel may be a chore depending on how much room it has left in it. You will probably have to get lug adapters for the neutral and ground. The only 125a breaker I have used is a Siemens. It will take a 2/0, but it's gonna be tight.

 

[Jim greengo]

The next home inspector I meet who knows anything about electrical beyond checking GFCIs and grounds will be the first one.

Exactly. If I had a dollar for every actual code violation I had to walk by to fix something a home inspector wrote up I'd be living on a beach.

 

[Jim greengo]

No, it is not a problem. To emphasize- the standard is that it not be "subject to physical damage." This does not mean it needs to be protected from all conceivable methods of mayhem.

Depends on your location. In everyplace around here but Omaha physical protection applies to everything below floor joists and walls.
In Omaha on the other hand we cant have any exposed wiring outside of conduit period in unfinished basements other than low voltage wiring.

 

[DerStig]

I have called and left a VM to the electrical inspector of my town to see if SER on joist ends is OK.

I am a little concerned though about the size of this wire. Someone said that it will be tough to fit on 125A breaker (feeder). Looking at siemens 125A, he is right. The 2/0 AL wire conductor is pretty massive.

 

[u2slow]

Modern compressed-strand alum wire is 'small' for its gauge. You can usually fit a size larger than a lug's rating, in my experience.

 

[DerStig]

Modern compressed-strand alum wire is 'small' for its gauge. You can usually fit a size larger than a lug's rating, in my experience.

I checked the breaker’s documentation and it supports 8-2/0 wire. So its right there.

That being said, our inspector says “subject to damage” areas need protection. This includes (he would not comment on ceiling) the points at which the cable leaves the main panel towards ceiling and then also comes down from ceiling.

The point at which this install is not easy is where the cable leaves the main panel. Its very crowded there. If I am going to install conduit there, I might as well do the entire thing. Also for the 2/0 SER, I would need 2” for sure which is massive. Whereas #1 THHN can be done with 1 1/2”.

 

[u2slow]

Can you go with MC in #2/0 alum affordably? That should satisfy any protection aspect. It should work fine with in 1-1/2" or 1-1/4" connectors and fittings.

http://www.caledonian-cables.net/product/special cables/Aluminum Conductor.html

 

[DerStig]

Can you go with MC in #2/0 alum affordably? That should satisfy any protection aspect. It should work fine with in 1-1/2" or 1-1/4" connectors and fittings.

http://www.caledonian-cables.net/product/special cables/Aluminum Conductor.html

That stuff is pretty expensive. I think the cost would be similar to the conduit based solution.

$1.42/ft is #1 CU THHN. $0.45/ft is #6 CU. For 45 ft thats $211.

1 1/2” PVC Conduit for 45 ft (including pull boxes, prebends) is $45.

Total is $256.

That stuff cheapest I found is $7.50/ft. By itself it is $338 and I dont know if MC cable can go through a brick wall, I might still need to sleeve it with some conduit.

 

[u2slow]

That stuff is pretty expensive. I think the cost would be similar to the conduit based solution.

Darn. Even at the supplier/wholesaler level?
https://www.wireandcableyourway.com...luminum-conductors-250ft-or-1000ft-spool.html

For my shop, I transitioned the MC (ACWU) cable to an LB fitting with about 8" of conduit on the end (2x compression EMT fittings) to poke through the wall. Land directly into the back of the box or panel.

 

[7635tools]

I personally would do conduit all the way. When I ran power out to my shop 15 years ago, I trenched in a 2” pvc for power, a 1” pvc for phone/data. At the time I only needed 100a so pulling the #3 copper out there was easy. Fast forward 10 years and when the bigger machines started showing up, I needed to supply more power out there. Thank good I ran an2”. Pullled the #3 copper out and put in 3/0 copper. I piped it in 2” emt across the basement, LB’d out the side of the house to the pvc. Total run 60’ outside in the trench and 30’ across my basement. It doesn’t take that much longer to run pipe, not mention it looks way better. Bending the 3/0 around in the house panel was a little tight but it’s doable.


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[TRWham]

Can you go with MC in #2/0 alum affordably? That should satisfy any protection aspect. It should work fine with in 1-1/2" or 1-1/4" connectors and fittings.

http://www.caledonian-cables.net/product/special cables/Aluminum Conductor.html

That is not clear at all. A particular inspector or AHJ might allow one and not another as a matter of local policy, but MC, AC and FMC all have the same restrictions in NFPA 70 as NM-B (or SER run as NM-B) when it comes to being "subject to physical damage."

 

[u2slow]

That is not clear at all. A particular inspector or AHJ might allow one and not another as a matter of local policy, but MC, AC and FMC all have the same restrictions in NFPA 70 as NM-B (or SER run as NM-B) when it comes to being "subject to physical damage."

Doh. My bad. Thought it 'universally' met the requirement under most/all jurisdictions.
(NFPA 70 not applicable to me.)