ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Northern Tool Recalls Powerhorse Generators
by Admin - 02/25/21 09:49 PM
You will never guess
by gfretwell - 02/25/21 07:48 PM
Lock-down Thread
by Bill Addiss - 02/24/21 04:40 PM
New tool
by SMOKEYBOB - 02/15/21 04:59 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 21 guests, and 17 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Commercial Bldg roof rewire and move #182732 12/08/08 12:22 PM
Joined: Aug 2001
Posts: 545
aldav53 Offline OP
Moving all the electrical panels on the roof of a fairly large commercial building. There is a shed on the roof with SES diconnect panel and 120,208, 277/480v, 225a regular panels. I should be able to splice the 4/0, 350MCM, etc. wire with special crimps or connectors. They want to rerun the pipe coming from A/C's AH, Fans, etc raised about a ft and a half above the ceiling outside so roof repair work can be done now and later for leaks on the roof. Any ideas on the best way to do this? Is splicing the main panel feeders ok? The switchboard (SES)disconnects, ..can they be changed to a panel with breakers? They feed machines and some panels. Any help would be apprieciated. Hope I discribed this good enough. I've been doing elec work a long time and this one is challenging. I thought I would start with one panel at a time, and move to the next.
Is running the pipe above the roof, feeding the panel ckts sound ok? or should I stay below the roof inside and run the pipes? I will need quit a few junc boxes to splice the circuits and panel feeders. The panels on the roof are fed from down inside SES disc's.
I could put a junc box splice below the roof and poke up through the roof and run the feeder wires to the wall which is upstairs inside the bldg, or run them below the roof, then poke up through, where the panels will be above the ceiling inside.
Splicing large 350MCM feeder wires should be ok?
Should I use the same type, but new service section disconnect switches in the new wall inside.?
There are also contactors in the shed, I might try to illuminate them, unless needed.

The Golden Rule - "The man with the gold makes the rule"
Work Gear for Electricians and the Trades
Re: Commercial Bldg roof rewire and move [Re: aldav53] #182742 12/08/08 05:57 PM
Joined: Jul 2002
Posts: 680
walrus Offline
Conduits on a roof are subject to derating in 08 code.Not sure if you're on 08 or not

Re: Commercial Bldg roof rewire and move [Re: walrus] #182748 12/08/08 09:04 PM
Joined: Jul 2007
Posts: 85
WireNuts29 Offline
Sounds like alot of work, to acomplish what exactly? also if you put alot of splice boxes below the roof deck, there are more penetrations to seal up. Another thing would be a pain to trouble shoot depending on height of inside ceiling, can you get a lift in there, now? in the future?

Re: Commercial Bldg roof rewire and move [Re: WireNuts29] #182755 12/09/08 04:05 AM
Joined: Aug 2001
Posts: 545
aldav53 Offline OP
The idea is to be able to do roof repairs and also have the panels inside instead of in an outside shed.

The Golden Rule - "The man with the gold makes the rule"
Re: Commercial Bldg roof rewire and move [Re: aldav53] #182781 12/10/08 11:17 AM
Joined: Aug 2006
Posts: 356
Niko Offline
I don't know how much wiring is involved, but how about if you take the old wires out, extend the conduits at a desired height and repull new wires?
It may be a bit costly, but it will be a cleaner installation and less connection to worry about.
Depending on how the roof will get re-done, I would do the junctions on the roof, it is easier to work on VS inside on the high ceiling with a lift. (assuming it is a high ceiling)

Be kind to your neighbor, he knows where you live


2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Alan Belson
Alan Belson
Mayenne N. France
Posts: 1,803
Joined: March 2005
Show All Member Profiles 
Top Posters(30 Days)
MCosta 3
Popular Topics(Views)
275,386 Are you busy
209,282 Re: Forum
196,579 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3