View Full Version : Residential electrical service
BillSartin
Jul 27, 2013, 03:36 PM
What size aluminum conductors needed for a 200 amp, 240 volt single phase, residential service that is in PVC conduit and 400 feet long?
donf
Jul 27, 2013, 05:05 PM
Based on the information given, you would need 1000 kcmil conductors to keep the voltage drop below 3% and provide 200 amps at the main service panel.
stanfortyman
Jul 27, 2013, 05:17 PM
Based on the information given, you would need 1000 kcmil conductors to keep the voltage drop below 3% and provide 200 amps at the main service panel.Don, what are you basing this on? This is a bit absurd.
A) We don't really use the 3% number for services
B) We don't use the old 310.16 for residential single phase services
C) We don't use the full amperage when figuring voltage drop
Typically 250' is about the limit for "standard" service wire sizing. From there we go up in size until primary is the best bet.
I'd go with 250mcm AL up to about 350' or so. Then up another size to about 400' or a little more.
Best bet is to contact your local utility. They are usually the ones who will size this cable and tell you what to use.
hkstroud
Jul 27, 2013, 09:56 PM
Question for you Stan.
How do you pull 3 wires that size and 400' long through conduit. I couldn't get that much wire off my truck.
donf
Jul 28, 2013, 05:10 AM
Stan,
I used the Southwire voltage drop calculator. The options I used were:
Single phase - Aluminum Cable - 240 V - Conduit and a working 200 Amps at the end of the cable.
I know it is absurd, but that was what the OP asked for, 200 amp. Also, that is the site that TK told me to use.
Don
stanfortyman
Jul 28, 2013, 06:25 AM
How do you pull 3 wires that size and 400' long through conduit. I couldn't get that much wire off my truck.It's not fun, I tell you that. :/
stanfortyman
Jul 28, 2013, 06:26 AM
I know it is absurd, but that was what the OP asked for, 200 amp. Also, that is the site that TK told me to use.Well, we normally don't use the full 200A number, 160 would be the highest I would ever use.
Also, like I said, we use the other table for figuring single phase residential services, so the standard VD chart does not apply.
donf
Jul 28, 2013, 11:36 AM
Stan,
The way I interpreted the original post, the requester was asking for a main service of 200 amps from a distance of 400' to the nearest connection point with the Power company. There was no mention suggestion that the OP wanted to take an 80% to the amperage.
Also, the OP wanted Aluminum and was going underground and in conduit.
I applied the Voltage Drop suggested / recommended percentages because of the sheer distance. Given that there is no way a 4/0 conductor would ever be able to deliver that working load that distance.
A 250 kcmil Aluminum conductor will only deliver 200 amps across 182'. At 160 amps, the calculator I use would carry the 160 Amps half way.
Please educate me if I am not doing this correctly.