The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by gfretwell
10/24/16 08:46 PM
International Wire Colour Codes
by Tjia1981
10/23/16 12:08 PM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 14
HotLine1 7
ghost307 7
renosteinke 6
Potseal 4
Who's Online
1 registered (Webmaster), 303 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#62337 - 02/14/06 10:21 PM 347 lighting
Cinner Offline

Registered: 12/01/04
Posts: 77
Loc: Kelowna, B.C., Canada
Is it proper lockout procedure to shut off the other 2 phases sharing the neutral with thge circuit you are working on?

Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#62338 - 02/15/06 04:26 AM Re: 347 lighting
resqcapt19 Offline

Registered: 11/10/00
Posts: 2209
Loc: IL

#62339 - 02/15/06 05:03 AM Re: 347 lighting
pauluk Offline

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
With power left on two other phases sharing the neutral, if you lifted that neutral at some point you could end up with voltage on one side via the loads.

Not only would this represent a shock-risk to you, it could also unbalance the voltages on those other loads. Given a large load on one phase and a small load on the other, you could see the voltage across the latter rise to almost the phase-to-phase level.

#62340 - 02/15/06 06:16 PM Re: 347 lighting
renosteinke Offline
Cat Servant

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
You know, this is one thing NEVER mentioned in "lock-out' discussions. The same point also applies to single phase, multi-wire circuits- that is, where two 'legs' share a neutral!

I found this out the hard way...when a money changer was momentarily supplied with 220v...I really loved having to buy a $600 power supply (as part of a $100 add-a-receptacle job)!

An added clarification....if you are "downstream" of any point where the other circuits might be, then there is no need to isolate them as well. But is often the have all phases present in the run of lights, they all ought to be killed.

[This message has been edited by renosteinke (edited 02-15-2006).]


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals