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manual transfer switch and neutral #203693
10/19/11 09:51 PM
10/19/11 09:51 PM
Niko  Offline OP
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
I don't quite understand when/why the neutral needs to get switched when a generator is involved in a residential system. Can you explain please.

i am installing a manual transfer switch but am wondering if i need to switch the neutral as well?

Thanks


Be kind to your neighbor, he knows where you live

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Re: manual transfer switch and neutral [Re: Niko] #203696
10/20/11 12:27 AM
10/20/11 12:27 AM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 933
Chicago Illinois USA
The electrical system needs the neutral to be grounded at 1 and only 1 point.

If both your normal Service and your generator have grounded neutrals, when they are connected together you will have the neutral of the system grounded at 2 points, which is a no-no.

If your generator neutral is grounded, you need to switch the neutral; if your generator neutral is not grounded, you can allow it to be connected to the normal system's ground via the system's neutral.


Ghost307
Re: manual transfer switch and neutral [Re: Niko] #203697
10/20/11 01:44 AM
10/20/11 01:44 AM
Niko  Offline OP
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
Thanks Ghost,
they (the customer) will be installing a portable generator until a permanent one can be purchased.

Are neutrals usually grounded on the portable units? or it varies? and if it is grounded can i disconnect the neutral from the generator frame? Or i am messing up the listing?



Be kind to your neighbor, he knows where you live

Re: manual transfer switch and neutral [Re: Niko] #203698
10/20/11 02:48 AM
10/20/11 02:48 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,180
Estero,Fl,usa
There is usually a comment in the instructions of how to lift the bond in the generator if you are making this a non-SDS.
(not switching the neutral). I think Hondas come floating and most others are bonded from the factory.


Greg Fretwell
Re: manual transfer switch and neutral [Re: gfretwell] #203703
10/20/11 09:32 AM
10/20/11 09:32 AM
K
KJay  Offline
Member
Joined: Nov 2007
Posts: 763
MA, USA
Iíve never switched a neutral on a resi transfer switch, whether automatic or manual. I just make the appropriate change to the ground connection at the generator itself.


Re: manual transfer switch and neutral [Re: Niko] #203705
10/20/11 10:07 AM
10/20/11 10:07 AM
Niko  Offline OP
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
OK. Thanks.

i think now my question turns to SDS. why would would someone choose not to remove the neutral. or any advantage of SDS or non- SDS?

i know the definition of SDS but i dont think i have a 100% grasp as to why you would have one or wouldn't.



Be kind to your neighbor, he knows where you live

Re: manual transfer switch and neutral [Re: Niko] #203707
10/20/11 11:39 AM
10/20/11 11:39 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,180
Estero,Fl,usa
I can't think of any good reason to create an SDS in 120/240v systems. Usually you apply this when you would be changing from delta to wye or some other significant system change.


Greg Fretwell
Re: manual transfer switch and neutral [Re: Niko] #203708
10/20/11 11:41 AM
10/20/11 11:41 AM
S
sparkyinak  Offline
Member
Joined: Jul 2007
Posts: 1,328
Alaska
Check with your POCO. a few years ago, I saw a commercial for another POCO and they had a shot on a xfer switch and wasn't switched. I contacted them and they said they didn't want the neutral switch


"Live Awesome!" - Kevin Carosa
Re: manual transfer switch and neutral [Re: Niko] #203710
10/20/11 11:43 AM
10/20/11 11:43 AM
Niko  Offline OP
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
OK thank you for the replies.


Be kind to your neighbor, he knows where you live


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