200 amp service ?s

[mcnair06goat]

Hey guys been a while since I posted on here. Anyway I am in the electrical phase of the build. I have a new service being put in and it coming underground to the shop. I have my panel and meter base ready to mount and I am asking u guys if I can use 4/0 copper thhn cable for the panel. What are the codes for 200 amp install with that type wire instead of the normal al wiring.

 

[Aceman]

You only need 3/0 THWN copper for 200 amps.

 

[mcnair06goat]

It was free wire can I not use it

 

[Aceman]

It will work fine.

 

[mooseeater19]

Bob,s your uncle , bury it before the crack heads get it.

 

[Speedy Petey]

I'd strip and scrap the 4/0CU, buy 4/0AL, and pocket the difference.

2/0CU would also be acceptable.

 

[Aceman]

I'd strip and scrap the 4/0CU, buy 4/0AL, and pocket the difference.

2/0CU would also be acceptable.

Do you always use dwelling wire sizes for shops and garages?

 

[tdkkart]

And when you're all done running your 4/0 cable, the power company will come and splice it to the transformer with a couple short pieces of #6 or #8.
Never been able to figure out why they do that, but I've seen it alot.

 

[tdkkart]

Do you always use dwelling wire sizes for shops and garages?

200 amps is 200 amps, just because it's a "shop" does not make it special.

 

[kiatech]

4/0 is only rated to 200 amps in industrial/commercial

 

[mcnair06goat]

I'm also running it through 2 or 2 1/2 inch conduit through the back of the meter straight to the panel where the main breaker is. Am I suppose to use some kind of a squeeze clamp or something on the main wires? In the wall

 

[C96]

If the wire is listed as THHN only, you CANNOT use it underground. It must have a listing with a W such as THWN or THW etc.

 

[Speedy Petey]

Do you always use dwelling wire sizes for shops and garages?

Yes, when it's an accessory building in a DWELLING setting.
EVERY electrician and inspector I know allows this. It also depends on the load calculation.

 

[Speedy Petey]

If the wire is listed as THHN only, you CANNOT use it underground. It must have a listing with a W such as THWN or THW etc.

I am SO tired of reading/hearing this!
WHEN was the last time you purchased new wire that was not dual rated THHN/THWN???

 

[Speedy Petey]

4/0 is only rated to 200 amps in industrial/commercial

Really? Must be a local code in your area.
I wonder why they do this? I also wonder how they can specify "industrial/commercial" like that.

 

[Norcal]

Yes, when it's an accessory building in a DWELLING setting.
EVERY electrician and inspector I know allows this.

Not what the NEC says, since nothing give permission for anything other then the conductors supplying the ENTIRE load of a dwelling,& a shop/garage/outbuilding fails to meet that criteria .

It also depends on the load calculation.

This is the only way one can do it IMO.

Comments in bold, I know it is quite common & the place is not going up in flames because 2/0 was used in place of 3/0, but it's still not meeting the requirements of 310.15(B)(6).

This is from the '08 which will be useless to me in a few weeks way past time to reload the 2011.

(6) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services
and Feeders. For individual dwelling units of one family,
two-family, and multifamily dwellings, conductors,
as listed in Table 310.15(B)(6), shall be permitted as
120/240-volt, 3-wire, single-phase service-entrance conductors,
service-lateral conductors, and feeder conductors
that serve as the main power feeder to each dwelling unit
and are installed in raceway or cable with or without an
equipment grounding conductor. For application of this section,
the main power feeder shall be the feeder between the main disconnect and the panelboard that supplies, either by
branch circuits or by feeders, or both, all loads that are part
or associated with the dwelling unit. The feeder conductors
to a dwelling unit shall not be required to have an allowable
ampacity rating greater than their service-entrance conductors.
The grounded conductor shall be permitted to be
smaller than the ungrounded conductors, provided the requirements
of 215.2, 220.61, and 230.42 are met.

 

[Speedy Petey]

I am WELL aware of how the code reads. It's just VERY common practice and VERY widely accepted. Hell, inspectors here don't bat an eyelash over #2AL 100A sub-panels either.

I see 4/0AL used here ALL the time for non-dwelling 200A services. I have even done it myself. If the inspector allows it under an acceptable load calc number I have FINE with it.

 

[C96]

I am SO tired of reading/hearing this!
WHEN was the last time you purchased new wire that was not dual rated THHN/THWN???

I hope Speedy has to read this again since he hates it so much….Lol.

The OP stated he got the wire for free…maybe a good reason for this. The wire is most likely not brand new and could have easily come from a spool that has been sitting around, or removed from a previous installation. There is plenty of wire out there with a single designation.

mcnair06goat, don’t forget to install a grounding electrode, this is also required for your project.

Good Luck on your build.

 

[Ross/Kzoo]

And when you're all done running your 4/0 cable, the power company will come and splice it to the transformer with a couple short pieces of #6 or #8.
Never been able to figure out why they do that, but I've seen it alot.

Having worked in the utility engineering dept for 38 years I can tell you that we many times sized the wire according to the load and not the capacity. Also. wire in free air (the overhead triplex wire) is able to withstand more ampacity than a wire in conduit. BTW the triplex is usually #4.

 

[mcnair06goat]

It is thhn/thwn II. I believe I also have to run 2 ground rods too.