Shared Neutral on multi-conductor cable

[Steven]

BE SURE TO USE POLARIZED PLUGS

 

I go even further by not using 2-pin plugs for my harnesses:

 

The left 8 channels are wired to a 9-pin Molex connector.

 

I also have some 3-channel and 4-channel harnesses:

The 4-channel harness doesn't use a common neutral. It just makes the set-up easier.

 

[Tim Fischer]

I didn't read all the above replies, since things seemed to get way off topic.  Sharing neutrals is fine IF you follow the following:

1) You understand what you're doing
2) Ensure the circuits feeding the controller(s) have the correct hot/neutral blade orientation (many outlets are miswired, and this can get VERY dangerous in this situation)
3) Make sure you don't overload the shared neutrals.  They need to be rated to handle the combined load from all hots that are sharing it.
4) As others have noted, don't share neutrals between different GFCIs.  In general, don't share them between "halves" of your controller, unless your controllers only have one plug, or you can guarantee they'll always be plugged into the same outlet (still bad practice).
5) You understand what you're doing. Repeating this one, because this can get dangerous quickly if you don't, both from a "shock hazard" standpoint and a "fire hazard" standpoint, not to mention blowing up equipment.

That said, I do this myself and it works just fine.

Good luck!

[Godney]

I can't seem to understand why people say your controllers halves cannot share the neutral without problems, when your whole house that means every plug, light ,etc. share only (1) neutral bar in your breaker box , if you open your panel their is (2) power legs (1) neutral bar And (1) gnd. buss now on older homes some share the neutral bar as gnd. and neutral thus showing only 2 power legs and 1 shared gnd/neutral bar. That is why i cannot understand some people saying  you cannot share the neutral between 2 halves of the controller when they come from only 1 buss bar.

Edited October 22, 2013 by Godney

[plasmadrive]

I think what they are saying is you can't share neutrals from different phases thru a single GFI, (unless it is made for that purpose like one for a spa).    The controller doesn't care...

 

This whole thing got off track from the OP and it is most likely my fault.  I turned it sideways.. but the discussion is interesting! 

[Tim Fischer]

I can't seem to understand why people say your controllers halves cannot share the neutral without problems, when your whole house that means every plug, light ,etc. share only (1) neutral bar in your breaker box , if you open your panel their is (2) power legs (1) neutral bar And (1) gnd. buss now on older homes some share the neutral bar as gnd. and neutral thus showing only 2 power legs and 1 shared gnd/neutral bar. That is why i cannot understand some people saying  you cannot share the neutral between 2 halves of the controller when they come from only 1 buss bar.

The GFI outlet will measure the balance of current between the hot and neutral and trip if it's not equal (within a certain tolerance).  If you have the controller plugged into 2 different GFCI's and share neutrals, you'll trip one GFI if not both. 

As I said in my post if the controller is plugged into only one GFI then you're fine. 

With standard residential service what phase you are on don't matter at all, period.