ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 265 guests, and 15 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#62337 02/15/06 02:21 AM
Joined: Dec 2004
Posts: 78
C
Cinner Offline OP
Member
Is it proper lockout procedure to shut off the other 2 phases sharing the neutral with thge circuit you are working on?

#62338 02/15/06 08:26 AM
Joined: Nov 2000
Posts: 2,148
R
Member
yes


Don(resqcapt19)
#62339 02/15/06 09:03 AM
Joined: Aug 2001
Posts: 7,520
P
Member
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 10:16 PM
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
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 if...as is often the cas...you 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).]


Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5