ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
VDE 0100 to introduce AFCIs
by sparky. 01/19/18 08:03 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 6 guests, and 13 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
320A MB into 2 200A MDPs? #23748
03/26/03 09:04 PM
03/26/03 09:04 PM
sparky66wv  Offline OP
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
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


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Work Gear for Electricians and the Trades
Re: 320A MB into 2 200A MDPs? #23749
03/26/03 09:35 PM
03/26/03 09:35 PM
E
Electric Eagle  Offline
Member
Joined: Apr 2002
Posts: 914
Alpharetta, GA
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.

Re: 320A MB into 2 200A MDPs? #23750
03/26/03 09:40 PM
03/26/03 09:40 PM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,918
Brick, NJ USA
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


John
Re: 320A MB into 2 200A MDPs? #23751
03/26/03 10:20 PM
03/26/03 10:20 PM
sparky66wv  Offline OP
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
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!

[Linked Image]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 320A MB into 2 200A MDPs? #23752
03/26/03 10:36 PM
03/26/03 10:36 PM
T
txsparky  Offline
Member
Joined: May 2001
Posts: 552
Magnolia,.Texas U.S.A.
Quote
This figure was using the 1990 Electrical Construction Estimator


Damn! There's no inflation in WV? [Linked Image]

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).]


Donnie
Re: 320A MB into 2 200A MDPs? #23753
03/26/03 10:42 PM
03/26/03 10:42 PM
sparky66wv  Offline OP
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
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...


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 320A MB into 2 200A MDPs? #23754
03/26/03 11:57 PM
03/26/03 11:57 PM
sparky66wv  Offline OP
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
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...


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 320A MB into 2 200A MDPs? #23755
03/27/03 12:40 AM
03/27/03 12:40 AM
T
txsparky  Offline
Member
Joined: May 2001
Posts: 552
Magnolia,.Texas U.S.A.
Quote
an average of $20 per man-hour


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


Donnie
Re: 320A MB into 2 200A MDPs? #23756
03/27/03 05:42 PM
03/27/03 05:42 PM
F
fedup  Offline
Member
Joined: Oct 2001
Posts: 31
alabama
The 320 amp meterbases I have seen are rated at 100% so it can be used on a 400 amp service

Re: 320A MB into 2 200A MDPs? #23757
03/27/03 06:55 PM
03/27/03 06:55 PM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,918
Brick, NJ USA
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


John
Page 1 of 2 1 2

Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Attic Rat
Attic Rat
Bergen Co.,N.J. USA
Posts: 524
Joined: December 2003
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
sparky 16
Potseal 15
Popular Topics(Views)
243,561 Are you busy
180,362 Re: Forum
170,840 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.020s Queries: 15 (0.004s) Memory: 1.0251 MB (Peak: 1.1974 MB) Zlib enabled. Server Time: 2018-01-20 08:52:44 UTC