ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Welded Copper Connections
by gfretwell. 04/19/19 04:46 PM
Norwegian power?
by dsk. 04/19/19 10:29 AM
Israel
by annemarie1. 04/18/19 02:35 PM
Water heater calculationsSo when I count calculati
by watersparkfalls. 04/13/19 12:43 PM
Health Canada Electric Construction heaters recall
by dougwells. 04/12/19 01:22 AM
New in the Gallery:
What is this for?
Plug terminals
Who's Online Now
0 registered members (), 7 guests, and 8 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
100 amp feeding 100 amp 250' away #10025
05/26/02 12:01 PM
05/26/02 12:01 PM
J
joeh20  Offline OP
Member
Joined: Mar 2002
Posts: 95
Tullahoma, TN, 37388
Good morning to the ECN thinktank.
My question: yesterday we refed a cabinet shop main panel, the panel is a GE 100 main breaker 20 circuit box. It was fed from a pole mounted 100amp meter and 100 amp disconnecting breaker underground about 50 feet away, 2 #2 al hots and 1 #2 al neutral, ground rod at pole #4 bare copper to meter nuetral bar, no ground from pole to shop 50 feet away. this week the pole has to come down.
We had a 200 amp panel in a building near the shop just lights and 20 recept, total load 25 amps max, we installed a 100 amp QO breaker in this panel and ran 250' 2 #2 al and a #4 neutral in conduit underground to existing GE 20 circuit panel in cabinet shop, we drove 8' ground rod and ran #4 bare to panel in shop and left out ground wire between buildings,
the question is with that distance and 100 amp breaker feeding 100 amp main with #2 al rated at 100 amps which breaker is the first to trip, and is that wire adequate to keep good voltage in the shop, the shop only draws maybe 50 amps with all the stuff running , and is the placement of the ground rod near the shop the safest way to do this.
Something tells me that this circuit is only good for about 75 amps max should the main panel in the cabinet shop been downsized to have been fed with 100 amp breaker 250' away.


Lighting the way
Work Gear for Electricians and the Trades
Re: 100 amp feeding 100 amp 250' away #10026
05/26/02 01:23 PM
05/26/02 01:23 PM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
Is this cabinet shop a "dwelling"?

If not, the #2 isn't big enough for 100A.

Table 310-15(b)(6) is for dwellings only.


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 100 amp feeding 100 amp 250' away #10027
05/26/02 03:42 PM
05/26/02 03:42 PM
J
joeh20  Offline OP
Member
Joined: Mar 2002
Posts: 95
Tullahoma, TN, 37388
it was an old house on the property, and with two additions now is a 1900 square foot cabinet shop. so it would be commercial by nature of the activity in it now.
I wondered about the wire size myself, the owner had purchased the material for the job and need someone to install, I felt he had the wire a bit small, especially with the distance.


Lighting the way
Re: 100 amp feeding 100 amp 250' away #10028
05/26/02 08:31 PM
05/26/02 08:31 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,372
joeh20
just some quick figures...
120V @ 250'>75deg USE>75deg term>in pvc>1 ph ac>=@5% drop using 250KCMIL al...


Featured:

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

 

Member Spotlight
mersadrad
mersadrad
Montreal, Quebec, Canada
Posts: 28
Joined: March 2011
Show All Member Profiles 
Top Posters(30 Days)
Popular Topics(Views)
254,472 Are you busy
190,717 Re: Forum
180,431 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.020s Queries: 15 (0.006s) Memory: 0.9601 MB (Peak: 1.0909 MB) Zlib enabled. Server Time: 2019-04-20 10:23:38 UTC