Office Bldg Service

recooper8 · May 14, 2004

I am looking at an office complex service entrance design. There will be 16 different offices (tenants) in one bldg and 3 offices in an adjacent bldg. The design calls for an outside pad mount transformer 3ph 120/208 feeding an outside disconnect switch (3ph OCPD). The disconnect would then feed 16 meters. Each meter would feed a 200 amp panel 1ph 120/208. A second lateral service from the transformer would feed another disconnect located on the the 2nd bldg and that disconnect would feed three meters and each meter would feed a 200 amp panel 1ph 120/208 inside the bldg.

1. Is this design allowed based on 230.40 Ex5?
2. Are two transformers needed?
3. Would it be allowed to have two disconnects on the bldg with 16 meters instead of one?
4. How far from the transformer can the disconnects be located?
5. Would the fault calculation be the same for both disconnects?
6. Any suggestions for improvement on this design?

charlie b · May 14, 2004

Re: Office Bldg Service

1. Yes.

2. No.

3. Yes

4. I don?t think there is a limit, but someone else may have a better answer.

5. No. The fault calculation takes into account the length of the cables from the transformer to the panel(s).

6. I haven?t the time today. Perhaps others can help.

hbendillo · May 14, 2004

Re: Office Bldg Service

4. The only thing that would limit the distance is voltage drop. If you get into distances over 200 feet I would do a voltage drop calculation.

6. The only thing I could offer is to not install a meter for each tenant. Install one meter and just put some money in the tenants rent to pay for utilities. That would save a lot of money on distribution equipment.

recooper8 · May 14, 2004

Re: Office Bldg Service

thanks for the quick response.

Office Bldg Service

recooper8

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charlie b

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hbendillo

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recooper8

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