# 115 VAC disconnect - should I break both hot & neutral?



## cbledsoe89 (Nov 16, 2015)

You only have to break the ungrounded conductor in a disco no need to break the neutral just pass through with it is my opinion but there are guys on here that have done it since before I was born so let some of them chime In on this


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## micromind (Aug 11, 2007)

There are very few times that it's required to break the neutral along with the hot. Explosion proof comes to mind......


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## Meadow (Jan 14, 2011)

No harm is done as long as the neutral is unfused and it opens/closes at the same time as the live.


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## RePhase277 (Feb 5, 2008)

Just so you know, the standard AC distribution to most buildings has a grounded neutral. Any modern wall outlet for general use has a grounded neutral. It's grounded just like your control transformer and for the same reason. There is a jumper at the service that makes the bond.


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## danhasenauer (Jun 10, 2009)

Do the neutral and ground conductors at the supply to your enclosure read continuity to each other? If yes, you don't need to have a disconnecting neutral. If your customer insists on one, just throw in a double-pole toggle with the toggle lock-off attachment in a handy box and call it done. (If the 115v supply is over 20a, then use a non-fused 2-pole blade switch)


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## Paul Kraemer (May 4, 2009)

Thank you all for your helpful responses. It seems like as long as the neutral and ground conductors at the supply read continuity to each other (which I will verify to be true), that I won't need to disconnect the neutral.

The disconnect I'll be using actually has three poles, so really its just a matter of whether I use just one of these or two. It seems as though there wouldn't be any harm in disconnecting the neutral, so I'll just ask my customer what they want me to do.

I could have done that in the first place, but I figured I would try to get some opinions here first to avoid asking the customer a stupid question.

Thank you all for your help!

Best regards,
Paul


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## JRaef (Mar 23, 2009)

Again, you DON'T have to, but you can if you WANT to.
But if you DECIDE that you WANT to, the device must break BOTH lines at the same time, so your 3P disconnect switch would do that.


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## oliquir (Jan 13, 2011)

if you use a 3 pole disconnect just cut both of them, it makes cleaner install


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## danickstr (Mar 21, 2010)

The only thing with a 3 pole disco is you must find a blank slug for the neutral phase


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## B-Nabs (Jun 4, 2014)

danickstr said:


> The only thing with a 3 pole disco is you must find a blank slug for the neutral phase


I don't think he's talking about a fused disco.


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## papaotis (Jun 8, 2013)

if in doubt, take the extra two minutes to wire the neutral to the switch!


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## Kevlarster (Sep 28, 2021)

Paul Kraemer said:


> Hi,
> 
> My company has been hired to build an electrical enclosure that will include four components that all work on 115 VAC single phase. This electrical enclosure is required to have a main disconnect. After installation, my customer will wire an incoming 115 VAC supply circuit that will power all of the components in my enclosure.
> 
> ...


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## Kevlarster (Sep 28, 2021)

I have the exact same question (480 3-ph designer for ages). A Google search brought me here and I am very pleased with the answers, thank you all so much.


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## paulengr (Oct 8, 2017)

The only time you have to break the neutral is when it’s not a grounded conductor. So service entrance disconnects for instance or if you have a disconnect for an instrument transformer or any other potentially “floating” cases are good examples. 

Another tricky one is a corner grounded delta where the incoming main is not fused because it’s the ground. The corner leg is a neutral, just not the typical one.

Another is when you don’t share grounds/neutrals like a backup generator with a separate ground from the utility ground.


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