200 Amp service on 2 AWG WIRE?

Al killian

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1,940
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Floydada, Tx
Well, finally got the permanent service turned on at the house and when they came out to run a new wire to the house they did two things that had me worried. First, they tapped into a line that feed a house next door. Then they only use 2 Awg alum wire. This seems to be way to small to run one 200 amp service let alone two houses. I am just nervous about hooking up any of the machine to the service and causing problem with the motors not pulling enough power. By the way everything in the house is electric. What should I do?
 
Who hooked up the wiring, the local utility or a private contractor? I'd get in touch with the building department or utility company. I'm no electrician, but everything I've seen 2 wire isn't even good enough for 100 amp service to code or mfg.
 
When I had 100A service extended to my shop, the contractor used #2 copper. What I've seen specified for 200A main service is 2/0 copper or 4/0 aluminum.
 
There are two rules for wire sizing, one for the utility company and one for the rest of us.

Utility companies are not bound by the National Electrical Code for the service drop to your house. Although you do have a 200amp service, you are likely to use only a portion of it at any particular time. Also, utility company with look at the transformer size feeding the houses and mountains of historical data when sizing service conductors/service sizes.

We have a single 37.5 kVA pole mounted transformer feeding four house (including my shop that has a separate 200amp service). Considering the transformer only outputs 156 amps and it has been there for forty years, shows that the power company knows how to size the services based on real world loads and not nameplate loads. Not everything is going to be running at one time, and if you do get a spike it is for a short duration. So they don't figure your actual loads will need more than they pulled to your house. If they are wrong and the extra heating of the conductors cause the insulation to break down, then they will fix/adjust it at that time. But 99% of the time they end up being correct.

It is not uncommon in the business/commercial world for power companies to only provide transformers/conductors at half the capacity of the rated service entrance equipment. In industrial applications where you can prove beyond a shadow of a doubt that your customer needs the full rated capacity of the service equipment, they will still only generally give you 80% of what you ask for. And again they are generally correct. Rob
 
Thanks Rob. Up in NY they use 2/0 wire when they ran wire from my shop to the road. Down here in TX it seems all the companies have there own set of rules for wiring.
 
When I had 100A service extended to my shop, the contractor used #2 copper. What I've seen specified for 200A main service is 2/0 copper or 4/0 aluminum.

#2 copper sounds correct. Aluminum wire has a greater resistance to current flow than copper. The specs above seem counter to that fact, #2 wire is bigger than #4, and with the added resistance - just doesn't sound right. Fortunately you got the #2 cu
 
#2 copper sounds correct. Aluminum wire has a greater resistance to current flow than copper. The specs above seem counter to that fact, #2 wire is bigger than #4, and with the added resistance - just doesn't sound right. Fortunately you got the #2 cu

Bill,

You missed the /0 after the numbers. 4/0 (0000) is bigger than 2/0 (00) wire.

Ike
 
If you have a local building code electrical inspector, call him/her and get their opinion......most of the building code inspectors I have been involved with concerning my home projects are quite amiable and will give advice freely.
 
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