Pardon my ignorance on services of this size:

I have a commercial bid for a service that will start out with a 320A meterbase, go to a disconnect, then be split into two 200A Feeders for two 200A Panels.

1) Does the Disco need to have Main protection at 320A? (Odd size...)

2) Does the Disco need to have two 200A Branch Circuit Protection, one for each feeder?

3) If not, how do I connect two 3/0 Cu Conductors to one lug?

I haven't done any services over 200A as a contractor and none after inspections were required, so I'm not sure if the way I was taught is right...

</pardon my ignorance>

Thanks in advance...

-Virgil

I know on residential we use a 320 MB with 2 - 200amp disco's. The MB will have double barrel lugs so you can go to each disco.(Sometimes we have to change the lugs)

I've never understood why they let us have 400 amps off a 320 meter.

I'm not sure if this helped you or not.

Virgil:
What you outlined is used for large resi around here. It's a 400 @ 80%. Commercial is usually all calc as continuous load....but that should be the call of your POCO.

If you need a main disco then it has to be a 400.

How about you do this:
Meter pan to a troff; parallel 3/0 & tie the ends together.
Get two 200 amp main CB panels.
Tap 1 set of 3/0 to each panel from troff.

The above is based on your panels being back-to-back with the meter, otherwise you need the disco at point of entry.

If the 320 meter base is unavailable....
Service into troff, either parallel 3/0 or 500 MCM
Tap 3/0 to each meter base (200 single meter)
Run to your panels.

John

Thanks guys, here's more info:

400A (320A Nominal) MB into 400A (320A Nominal) Disconnect with 500 KCM Cu.

Then, with double lugs on load side, splitting into two runs of 3/0 Cu (w/ a #4 EGC) to each 200A panel.

The MB and disco will be side to side, there is about 20' to the location of the 200A panels inside.

Then, the two original 100A panels will be fed off of the Lighting Panel (200A) off of 100A CB's and the new HVAC stuff will be on the Power Panel (200A).

The two 100A subs are 100' and 130' away respectively.

I'll have to core drill two 2-12" holes and 4 1-3/4" holes, and run the conduit to the subs above drop ceilings.

Also, the old panels will have to have ground busses and the EGC's seperated from the neutrals.

My horribly rough estimate is about $2700 for materials and about $1200 in labor.

This figure was using the 1990 Electrical Construction Estimator.

The underground lateral and conduit is not included in the bid.

Am I anywhere near the ballpark?

BTW: I'm bidding against a local Commercial Electrical Contractor who "has done all the work here" and could pull a profitable figure out of his hat and still have me beat... So I don't want to invest too much time in this.. The GC has the contract to convert the HVAC and would rather use me (probably because I'll lose money on it and he will gain from it...)

Help!

Damn! There's no inflation in WV?

FWIW, the labor sounds way low based on the amount of work that you described.(either that,or You and Jimmy are very fast)

[This message has been edited by txsparky (edited 03-26-2003).]

OK, I tweaked the figures with Electric Eagle's idea of two 200A discos, and it dropped it down to about $2600 Materials and up to $1300 in labor for a net of $3900...

Ends up about the same...

Sorry, Donnie, I missed your post somehow...

Actually, I had to lower the hourly wage figure from $26.26 in the book to an average of $20 per man-hour to be competitive...

And the materials vary from being either a little more or a little less than what they are here in reality. It comes close it seems...

Too low? Heck, I figured It'd be about $1000 "too high" from what the GC and Church are expecting to pay...

How many Man-hours would you count?

I figured on about 65...

Theres some of the difference!
I was thinking closer to 80 hours with it being an existing building in use and having to work around others and their schedules as well as cleanup.

Donnie

The 320 amp meterbases I have seen are rated at 100% so it can be used on a 400 amp service

Fedup:
"The 320 are rated 100%" then they are 320 amps, right??
I'm not trying to be a smarta**.

Virgil:
You are paralleling the 3/0 feeder(s) from the 400 amp main to the 2 panels....are they the same length??? You may want to go with the 2x200 discos; might be cheaper and easier.
Just a thought.
Good Luck with the bid!
John

They would not be parallel one set of 3/0 to each panel, to be parellel both ends would need to be connected together.

To come off the 400 disco and run to the panels you will have to apply 240.21(B)(2) and keep the length under 25'

The panels have 200 Amp MCBs right?


[This message has been edited by iwire (edited 03-27-2003).]

Yes, the two 200A Discos is the way I'll go with this, thanks.

Got the materials quote today, and looks like the materials will come closer to $1700 (deflation?) and I'll keep the labor in the 80 man-hour range as well.

Figure I'll ask for $3500, then let 'em drop me to $3300 so they'll feel good about themselves.

Yes, the panels will have MCBs.

Thanks for all the help!

Iwire:
Thanks for the correction.....must be a senior moment. My fingers did not type what my brain sent to them.
John

Virgil
I am quoting a similar service in which I am using a 400/320 amp meter main panel which has twin 200 amp breakers in it. It goes for around $500 where I am. Just a thought that it might save you some labor and time on the job.
Watthead

sparky66vw

this one i done quite a bit with large redistal home as long the breaker box is not over 6 feet from meter pedstel or socket this what i ran .

2- 200A 42 space boxes
2X 4/0 al wires (3 conducters)
a length of wireway thru then spit off with 2 inch conducts nipple each side of wireway and single ground wire 1/0 size or duplex ground wire #2 each

for labour wise it is 60 man hours ave but it can change depend on what it have on the strucure and location ( my most have basement) cost wise i really cant say it depend on what it setup and if any sub feed box are involved or not

i hope it can help you with that but if any question just drop the line here

merci marc