100 amp sub panel?

[clayton]

residential. feed to 100amp subpanel, (or whatever you want to call it), any problems with feeding this panel with say, use or uf? do they make a romex in #4awg?? reason was wanting to avoid conduit if possible.

thanks
clayton

[Tiger Electrical]

Real electricians use conduit.

Dave

[mdshunk]

I don't know if they make romex or UF that big, but SER would be the typical choice if a cable method is desired.

[360Youth]

Real electricians use conduit.

Dave

Where in the world does that come from?? I've pulled a lot of real NM in a whole lot of real homes. I'm tempted to make a new thread out of that statement alone.

To answer the OP, 100 amp SER would be fine. Skip the UF, IMO, in such an application. Make sure you check '08 NEC if it applies. Rules have changed regarding residential feeders.

[Cavie]

Real electricians use conduit.

Dave

Guess I've fooled a lot of people in 38 years!!:grin:

[clayton]

thanks for your answers,
now, personal preferance, #4 or #2?? what would you do and why??


i think personally i like conduit, it is a fine and code compliable installation, but so are various other wiring assemblies, and any real electrician should be willing to admit that, even if they prefer one over the other.

thanks again.

[quogueelectric]

residential. feed to 100amp subpanel, (or whatever you want to call it), any problems with feeding this panel with say, use or uf? do they make a romex in #4awg?? reason was wanting to avoid conduit if possible.

thanks
clayton
But you would have to go with a #3 or #2 to safely carry 100 amps. The number 4 is a residential service exception for services only.

[iwire]

Real electricians use conduit.

Dave

Yeah, that makes sense. :roll:

[iwire]

thanks for your answers,
now, personal preference, #4 or #2?? what would you do and why??

3 copper or 1 Aluminum would be the smallest legal sizes for a 100 amp sub panel. (Unless the service entrance conductors are smaller)

[chris kennedy]

Real electricians use conduit.

Dave

Look where Dave lives.

[iwire]

Look where Dave lives.

I 'know' Dave and I did know where he lives, his answer is still rude.

There are millions of "real electrians" that have never picked up a bender.

[Dennis Alwon]

Depending on the load of the subpanel, you can use #4 and use a 90 amp CB. That will save you some money.

I would use ser cable copper because the cable is rated 90C .. NM cable must be used at 60C

[CBL]

.
Make sure you check '08 NEC if it applies. Rules have changed regarding residential feeders.

You say check the '08 NEC...Are any states already using the '08? I thought most moved up to '05 at the beginning of the year...Thanks

[Dennis Alwon]

You say check the '08 NEC...Are any states already using the '08? I thought most moved up to '05 at the beginning of the year...Thanks

NC will be using 08 on June 1. I believe most states are using the 05 for years.

[CBL]

NC will be using 08 on June 1. I believe most states are using the 05 for years.
Thanks, I thought that most were on '05 and I just bought the 2005 NEC Code book and 2005 Handbook. Thanks

[Tiger Electrical]

The conduit remark was a joke because IMO it's dangerous to give advice to someone who asks if it's OK to run 4 ga UF for a 100-amp subpanel. Real electricians don't need to bend conduit, but they do need to read ampacity tables.

Dave

[Cavie]

The conduit remark was a joke because IMO it's dangerous to give advice to someone who asks if it's OK to run 4 ga UF for a 100-amp subpanel. Real electricians don't need to bend conduit, but they do need to read ampacity tables.

Dave

Where I come from, #4 would be just fine in the Sub panel. #4 is allowed for the service and it would be a waist of money to require the sub panel feeders to be larger than the service wires. Think about it. What would be the benifit?

[peter d]

Real electricians use conduit.


Darn, where do I turn in my license? :roll:

[360Youth]

The conduit remark was a joke because IMO it's dangerous to give advice to someone who asks if it's OK to run 4 ga UF for a 100-amp subpanel. Real electricians don't need to bend conduit, but they do need to read ampacity tables.

Dave


I'd rather they ask here or somewhere than do it wrong in the field. His questions seem a little rookie-ish, but I'll moderators sort that out.

[360Youth]

You say check the '08 NEC...Are any states already using the '08? I thought most moved up to '05 at the beginning of the year...Thanks

It's already been adressed, but I just was advising checking your local adoption. It does not matter what NC or MA is using, only where you are. I talked to some friends in MD over the weekend and I think she said DC is still on '99 or '02.

[clayton]

thanks again for all the replys.
no offense, dave, but if you didnt want to give any advice, then i believe iwire made it clear on the treatment of members point #2, that you have the option to just ignore the post and move on. it is a rookie-ish question but i thought we could ask questions here. If i new the answer already why would i ask the question? ive been a member here for years now, i browse the posts alot, then for several years i stopped because of how REAL electricians treated anyone who asked a simple question.

they were lambasted. wasn't necesary or warrented. thats why i have so few posts. However there are alot of members who have much more experiance than me and i appreciate their advice and code related dialogue, makes for interesting conversation at the shop.

thanks again all.

[LarryFine]

Depending on the load of the subpanel, you can use #4 and use a 90 amp CB. That will save you some money.
Maybe, maybe not. A 90a breaker can cost a lot more than a 100a breaker, due to supply-and-demand.

[satcom]

Maybe, maybe not. A 90a breaker can cost a lot more than a 100a breaker, due to supply-and-demand.

The 90A is always more, but he said he had 4 UF, that will not cut it for a sub panel feed, the neutral will have to be isolated, and the ground wire will need to be insulated UF cable is not insulated ground.

[racer6m]

check with ahj some may require pipe for sub panels

[Tiger Electrical]

I know my replies sound rude to some of you. I'll give you my perspective on it.

Several years ago I got an emergency call. The homeowner had a son who decided to do the electrical work on his addition. He moved live utility wires across the house, asked an electrician about the wiring connections into the new service and installed one leg on the main breaker and the other leg on the neutral bar. He turned on the main, noticed the insulation bubbling on the service wire and turned off the main breaker. He fried a lot of equipment in the house due to the over-voltage. The electrician he talked with was helpful, but should have told him he was over his head.

I don't recognize this poster, I do recognize Larry Fine, iwire and satcom from this and other forums. I link to my website. Most posters don't give any information about themselves. The question sounded non-professional to me. Until one of the more recent posts the issue of an insulated ground wasn't mentioned. There's another issue that still hasn't been mentioned. Are you being helpful or is he over his head?

Dave

[clayton]

so now we can only reply to posters we personally know???
this is crazy. remember , if you dont have anything nice to say.......

i was curious as to alternative methods for feeding a 100 amp subpanel(load center) #4 or #2 ser, use, or prehaps #2/3wg romex. instead of 1 1/2 conduit and #2 or 1 1/4 with #4, sorry you dont have my card and credentials, sorrry you dont know me, what is it with this site?

fine, 8yr union jrnymn, 2yr associates degree, electrical technology, 2yrs working for resi, comm, ind, contractor as helper,

sorryyyyy i dont know everything. and sorry for asking for help if i did feel over my head. cuzz i wouldnt want to look like a fool or something, just hook it up say a prayer and if the light comes on its good.


(im playing devils advocate here because this kind of thing gets on my nerves and posssibly others.) answer the question or don't, you don't need my personal data, would it have been ok if an apprentice asked? or a student?


before i asked i tried searching to no avail, and was pretty certain that this is what would happen when i asked a ?

[Tiger Electrical]

clayton, there's a lot I don't know too. I don't want you to kill yourself or your family. I know I could be more helpful. Since you're an electrician please study Article 250 on grounding. This article is vital for safe subpanels.

Dave

[iwire]

Where I come from, #4 would be just fine in the Sub panel. #4 is allowed for the service and it would be a waist of money to require the sub panel feeders to be larger than the service wires.

If the service is 125, 150 200 amps etc. it is an NEC violation to run 4 AWG to a subpanel with 100 amp OCP.

If the service was 100 amps, run with 4 AWG and the sub panel OCP was 100 then yes you could also run 4 AWG to the sub.

Think about it. What would be the benefit

I have thought about, and I have read the CMP comments about it and have decided the benefit would be code compliance. :smile:

[iwire]

I know my replies sound rude to some of you. I'll give you my perspective on it.

Dave, all new members here have their post checked and approved by a moderator.

If you feel the person is unqualified, don't answer, this applies to everyone.

Please follow the link

Treatment of New Members (http://forums.mikeholt.com/showpost.php?p=714828&postcount=2)

[iwire]

but he said he had 4 UF, that will not cut it for a sub panel feed, the neutral will have to be isolated, and the ground wire will need to be insulated UF cable is not insulated ground.

4 UF could be 4/2, 4/3, 4/4 etc.

[infinity]

4 UF could be 4/2, 4/3, 4/4 etc.


That's what I thought. Even the local Big Orange sells some of that stuff with 4 conductors.

[Dennis Alwon]

Maybe, maybe not. A 90a breaker can cost a lot more than a 100a breaker, due to supply-and-demand.

Not around here it doesn't. Beside that could be offset by the cost of the wire.

4 UF could be 4/2, 4/3, 4/4 etc.

Thank you that is exactly what I thought.

[clayton]

thank you dave, i will intently study 250.

[clayton]

iwire, were could i look or be certain that a #4 cu wire would be a code violation??, thanks

[LarryFine]

iwire, were could i look or be certain that a #4 cu wire would be a code violation??, thanks
310.15 and .16.

[Dennis Alwon]

iwire, were could i look or be certain that a #4 cu wire would be a code violation??, thanks

Look at Table 310.15(B)(6) and the art associated with it rt. 310.15(B)(6). Notice the conductor types at the top of the table. I would also read art 340.80 ampacity for UF

[kbsparky]

Why not consider using conduit? We use PVC conduit all the time for such installations, and never have to "pick up a bender" as someone pointed out. :grin:

With PVC, you can install #3 hots, a #4 neutral, and a #8 ground. And, you can bury the stuff if necessary. It will fit into a 1" size, although I would recommend at least 1¼" if the run has any significant length to it.

Typical for a 100 Amp feeder. ;)

[jamesguy10]

where the heck do you get a #4 neutral from?

[kbsparky]

where the heck do you get a #4 neutral from?Usually at the supply house. :D


Oh, you mean how do I justify installing a reduced neutral conductor? Try 220.61(A).

[zdog]

The 90A is always more, but he said he had 4 UF, that will not cut it for a sub panel feed, the neutral will have to be isolated, and the ground wire will need to be insulated UF cable is not insulated ground.
have i been missing something here?where in the code does it say the ground has to be insulated?250.119 says bare,covered or insulated.here we mostly use ser for sub panels or services where the panel and meter are not back to back and we have to use outside disconnect.which would make the main panel a sub panel right? ser has two hots netural insulated and a bare ground.