320 amp service

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All Amped Up

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overhead service . i'm thinking 4/0 seu to meter socket. drop parallel 2/0 to troff which feed (2) 150 amp rain tight main disconnects. 2/0 ser to (2) 200 amp 32 circuit -main lug panels. should i use a troff or 2/0 seu w/ weather proof connectors below disconnects? any suggestions...
 
I think 4/0 to the meter is a bit small.

Do your disconnects have to be outside?

A trough is the better install, SEU will be cheaper. Not so sure you need a weathertight connector on the bottom of an enclosure.
 
All Amped Up said:
overhead service . i'm thinking 4/0 seu to meter socket. drop parallel 2/0 to troff which feed (2) 150 amp rain tight main disconnects. 2/0 ser to (2) 200 amp 32 circuit -main lug panels. should i use a troff or 2/0 seu w/ weather proof connectors below disconnects? any suggestions...
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Are you really only wanting a 300 amp service? A 320 amp meter base is capable of 400 amps as long as it is not continuous. It is rated 320 (400 * 80%) for continuous loads.

Wire size means nothing without knowledge of copper or aluminum. I assume you are using 2/0 aluminum. Yes it is good for 150 amps if it is the totally load of the service. However if you go to 2- 200 amp 32 cir. panels and you are expecting 150 amps at each panel then you must use 4/0 aluminum based on the 2008 code. Read art. 338.10(4)(a) which refers back to 334 part II--- 334.80 says that seu must be used at 60C as a feeder.
 
All Amped Up said:
drop parallel 2/0 to troff which feed (2) 150 amp rain tight main disconnects. 2/0 ser to (2) 200 amp 32 circuit -main lug panels. should i use a troff or 2/0 seu w/ weather proof connectors below disconnects? any suggestions...
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I would install a meter with two 200amp disconnects already installed, If the disconnects are actually needed at the outdoor location, otherwise I would install two 200amp main breaker panels as soon as the SEC's entered the structure.
 
I'll use 4/0 ser as my sub feeders. (2) 200 amp 32 circuit panels . disconnects must be outside.

what should i use for my service drop?
 
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my load calc only requires a 200 amp service. the guy has future plans. addition , hot tub , pool , 10kw heat. its a beach house. like 2 families at a time. i just want a little extra
 
Bob's point was that the service riser only has to be as large as the calculated load. Obviously it would be smart to install a larger riser if the loads are likely to increase. This is why I stated the wire sizes in my post #6
 
Dennis Alwon said:
Bob's point was that the service riser only has to be as large as the calculated load. Obviously it would be smart to install a larger riser if the loads are likely to increase. This is why I stated the wire sizes in my post #6
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Within limits. If you have a single main disconnect, the service entrance conductors (SECs) must be rated for the size of the main disconnect or within a "round up" of that disconnect rating. With two disconnects, you could legally install SECs for 200A and have two 150A or two 200A disconnects as long as the calculated load was 200A or less. But that would be misleading. Installing a meterbase over 200A is mostly worthless if the SECs can't do more than 200A.

What size service is the guy paying for? If he wants a 300A service, then you should install conductors that will support that. See 310.15(B)(6) for sizing residential SECs. For aluminum, it says 350 KCMil for 300A, 500 KCMil for 350A, and 600 KCMil for 400A.
 
suemarkp said:
With two disconnects, you could legally install SECs for 200A and have two 150A or two 200A disconnects as long as the calculated load was 200A or less. But that would be misleading.
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There is nothing misleading about it, it is done all the time.

Here is a 225 - 250 amp riser protected by six 100 amp breakers.

Dennis8.jpg


Whoever adds to the load is responsible to make sure the service can handle the load.

What size service is the guy paying for? If he wants a 300A service, then you should install conductors that will support that.
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That I agree with 100%. :smile:
 
I know its done all the time, but my point was more along the lines of the advertised service size. If you said you installed a 600A service on that multi 100A panel setup, but only provided a meter and SECs for 250A, I'd say that was misleading. If someone asks for six 100A services to a multifamily building, then what you have in the photo would be just fine.
 
suemarkp said:
I know its done all the time, but my point was more along the lines of the advertised service size. If you said you installed a 600A service on that multi 100A panel setup, but only provided a meter and SECs for 250A, I'd say that was misleading. If someone asks for six 100A services to a multifamily building, then what you have in the photo would be just fine.
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I guess you have to play with words sometimes to competitively bid.
 
suemarkp said:
I think 4/0 to the meter is a bit small.

Do your disconnects have to be outside?

A trough is the better install, SEU will be cheaper. Not so sure you need a weathertight connector on the bottom of an enclosure.
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Watertight connectors are required outdoors. period
 
All Amped Up said:
I'll use 4/0 ser as my sub feeders. (2) 200 amp 32 circuit panels . disconnects must be outside.

what should i use for my service drop?
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you should use 2 600kcmil al and a 400kcmil al for your line side. Then 2- 4/0 al seu for your loadside. What people fail to realize is that 4/0 seu / ser is good for 200 amps if using for residential use but must be derated at 60 deg to 150 amps if used for commercial use only not residential.
 
suemarkp said:
I know its done all the time, but my point was more along the lines of the advertised service size. If you said you installed a 600A service on that multi 100A panel setup, but only provided a meter and SECs for 250A, I'd say that was misleading. If someone asks for six 100A services to a multifamily building, then what you have in the photo would be just fine.
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The service in the picture was done by a friend of mine, the customer did not ask for a certain size service, he wanted a new and legal service as cheap as possible.

I did agree with you above about providing what the customer asks for and have said so many times on this forum.:smile:
 
iwire said:
mike that is false

check out the last sentence of 312.2(a)



Got a code section in mind?
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any ahj will quote this.

as for 312.2(a)
yes but what it should have read is like this:

When installing entrance cable, a watertight connector shall be used at the top of the meter base, and a non-watertight connector shall be used at the bottom of the meter base,
for drainage.
 
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It's great to see the regional differences in our trade. What is standard in one section of the country may not be allowed elsewhere. It's been a long time since I have seen SEU stapled on the siding
 
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