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Joined: Jul 2004
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Thanks for the input. Let me paraphrase ITO: 800A main disconnect. Tap box/tap block gutter House meter 277/480V house panel 10KVA 1 ph xformer 120/240 1ph house panel (I think the only thing that may be on this is a heater for the water service hot box). My local utility requires a disconnect ahead of a 480V meter. But this building is not local for me (it is NiMo I think). What 100A (or 200A) 480V meter will give a short circuit rating above 10K? What am I missing?
Last edited by cgw; 05/23/07 01:48 PM.
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Joined: Nov 2006
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How is the service being metered?
Gutter needs to be N3R and long enough for all the tenants.
I don't think your meter has anything to do with available fault current; around here we don't select or furnish a meter, that part is all done by the poco. We just install an approved meter can that the poco sell us or is sometimes furnished to us as part of the permit.
Last edited by ITO; 05/23/07 02:08 PM.
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I mean the meter socket. I.E. a Cutler Hammer 100A meter socket has a short circuit rating of 10KA.
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Joined: Nov 2006
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Hmmm I have never bought one from a supply house, we get ours from the poco in my area.
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Joined: Apr 2002
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CGW: Your utility have any "approved" meter stacks?
We have run 600 to 1600 into a Sq D stack. 3 phase, 4 wire, 277/480 with 200amps to each tenant space. 100 amp 480 feed to 75 kva xfr to 42 circ 120/208 w/200 or 225 MCB.
For anything above 200 self contained (w/CT cab) a plug-in section w/?? MCB to CT & then to space.
Our utility requires 'cold sequence', so main before CT/Meter.
John
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They may or may not put a tanning salon in. I was thinking that a typical salon may have 5 beds. Was I off. I understand they probably would have more like 30 or more. Here are some numbers: Tanning Salon 3000 SF, 160,000VA Bar/Rest 4000 SF, 100,000VA Remaining 8000SF, 20VA/sf - 160,000VA That's 505A at 480V. So 600A would work. 800A would be conservative. 1200A would be ridiculous. What do you think?
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Joined: Nov 2006
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If you do not know what is going into the lease space, and your client does not either, its completely ludicrous to design for ANY load that may or may not go in there. You are either doing a budget, or a bid and if you plan on all the worst-case scenarios then you will be too high and wont get the work.
The solution is very simple, plan on an agreed upon VA per SF, in this case 22 worked well for a 400A HV service, then make sure you bring in your empty spare conduit from the service transformer to where you can use it later as provisions for any restaurants and tanning salons.
I have done enough of these to know that all restaurants and salons know they will have to pay for upgrades to the service to build out their lease, unless they make their deal on the front end of the project being built, and even then they still pay something to get it done. This is where your provisions from the transformer come in, if they are needed.
If the client wants 60/SF then price it and give it to him with a VE for 22/SF so when he thinks you are way too high and shops your number at least he has your VE before the next guy gives him a VE just like it.
Just my two cents, we could site around continue to mentally masturbate this to death but the fact is if you don’t know what is going in these spaces and you want the work, then the solution is a clear scope with an agreed upon va/ft, provisions for more (empty conduit) and a contract that states all this.
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HotLine1 - Does Square D have meter stacks rated at 480V?
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Joined: Apr 2002
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Sq D has 480 volt, see Section 9 of Digest Class 2755, 2756 or 2710. You MUST check with your utility first for ANY mfg equipment. CH/Siemens, etc are also available.
John
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