ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
How's Florida doing with Hurricane Ian?
by Bill Addiss - 09/28/22 12:41 PM
Tough being a lineman's kid
by Bill Addiss - 09/28/22 12:39 PM
GFCI's pops in large numbers
by dsk - 09/26/22 04:35 AM
AFCI’s Revisited
by sparky - 09/24/22 09:58 AM
NFPA Price Increase Coming
by Bill Addiss - 09/23/22 02:22 PM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
1 members (Scott35), 17 guests, and 10 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: May 2001
Posts: 160
C
Member
I am concerned about opening a switch or receptacle box in a residence and finding a multiwire circuit,2 ungrounded(hot) and a shared neutral with the hot conductors measuring 240 volts between them.I believe this is allowed per the NEC to share the neutral and feed the circuits from both sides of the panel in order to reduce the neutral current thus allowing for only one neutral conductor.
This appears to me to be a saftey issue and maybe there should be a notice posted on the box stating that 240 volts is present.
What is the opinion of the group?

Joined: Oct 2000
Posts: 5,392
S
Member
Hi Chris,
this would be a 'multiwire branch circuit'.In a dwelling, the only change would be 210-4(b), which would require a double pole circuit breaker. the rationale, i imagine, is for the protection of the homeowner DIYer,as the normal 120v receptacle would be taken at face value.

[Linked Image]

Joined: Nov 2000
Posts: 123
D
doc Offline
Member
well in my opinion I do not think they should be allowed at allfor my part they are very dangerous esp when trying to tie into and existing grounded conductor and you find out it is a neutral,and yes I agree with you about the warning.
On another forum in 1 week there was 2 different people asking about the outlets not working on bottom but was fine on the top and another had replaced some outlets and had problems
both casses were multi wire circuits that were not installed with the breakers tied together and the other guy thought they were 120 oulets and had no idea to cut the brass link


MAY THE SUN SHINE ON YOUR FACE IN THE MORNING AND YOU AWAKE WITH A SMILE
Joined: Mar 2001
Posts: 2,056
R
Member
2 separate duplex receptacles in the same box do not seem to require a 2-pole breaker. Only if 2 halves on a single yoke are split. There are advantages to multi-wire ckts. though. Less voltage drop, less material cost, less box fill. Obviously, safety comes first, but this is sometimes a competitive game. Always be aware.(EASIER SAID THAN DONE)

Joined: Oct 2000
Posts: 5,392
S
Member
Redsy;
only if on the same yolk!
thanks for the reminder..
[Linked Image]

Joined: May 2001
Posts: 160
C
Member
Sparky,Doc and Redsy,
Thanks for the reply.

Chris Rudolph's Power Factor

Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
Chris,

This is not much of a safety issue or it would likely have been changed in the code by now.

First off, only qualified persons should be working on an electrical system. Henry Homeowner isn't qualified & this trade is not a hobby.

If you are a qualified person, you should know all about multi-wire circuits & you shouldn't be working on them hot with the possible exception of taking a measurement.

What box would you require the 240 volt sign on? If it is a warning sign put on the panelboard, this might not be a bad idea, perhaps you could submit a proposal for the 2005 code cycle.

Tom


Few things are harder to put up with than the annoyance of a good example.
Joined: May 2001
Posts: 160
C
Member
Tom,
Thanks for the reply.I was thinking about a stick on label in side a single or more ganged box just hoping that Henry homeowner would give pause and immediately replace the cover plate.It would also serve as a reminder to us folks that have senior moments now and then.
Chris


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

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

 

Member Spotlight
Vlado
Vlado
Croatia
Posts: 28
Joined: February 2011
Top Posters(30 Days)
dsk 3
Popular Topics(Views)
297,768 Are you busy
228,511 Re: Forum
213,342 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5