Do split phase boards exist?

gazj82 · Oct 17, 2013

Living out in the sticks. I have come across old split phase installations a few times and done a little maintenance on them. These installations usually consist of a old 3 rewireable db with only 2 phases used.

Well for the first time I have been asked to add some circuits which requires a new board. Do split phase boards exist? Or do I follow the convention of old and just use a 3 phase board and only connect my 2 phases in the bottom of the main switch? Obviously clearly marking on the front of the board that it is not connected in the standard convention.

D Skelton · Oct 17, 2013

Are you sure it is true split phase and not just two from three? If so, your going to have real trouble finding LV dis boards rated above 400/415V at 460/480V

Marvo · Oct 17, 2013

I've never seen a board that was manufactured as a split phase board. Specifying suitably rated components can be a a problem with the higher phase to phase voltage.

*edit* Beaten to it by Mr Skelton who obviously uses more than one finger when typing

gazj82 · Oct 17, 2013

It could well be 2 from 3, rather than split phase at 180o. Either way still need to know if using a 3 phase board is acceptable on a 2 phase system. I must admit I hadn't thought about boards not being rated for 480v.

netblindpaul · Oct 17, 2013

Remember also that "most" 3ph DB manufacturers will state that their boards are unsafe @ split phase voltages!

D Skelton · Oct 17, 2013

gazj82 said:
It could well be 2 from 3, rather than split phase at 180o. Either way still need to know if using a 3 phase board is acceptable on a 2 phase system. I must admit I hadn't thought about boards not being rated for 480v.

If it is just two from three you can use what you like. Use a SP DB with a three pole instead of two pole isolator (providing voltage rating is appropriate) or a TP DB with two phases linked within.

If it is indeed a split phase supply which I highly doubt you may find yourself up poo creek withou a paddle when it comes to an all inclusive distribution arrangement. Keep both phases split from the head and kept as two entirely seperate phases.

gazj82 · Oct 17, 2013

Thanks that helps loads. If it is indeed split phase then I could install 2 single phase boards to keep my loads balanced. Just seems a little silly, especially as the future could hold an upgrade to 3 phase. If it is indeed 2 derived from 3 then I'll go with a 3 phase board from the go.

Thanks for you help

D Skelton · Oct 17, 2013

gazj82 said:
If it is indeed 2 derived from 3 then I'll go with a 3 phase board from the go.

It's your call and no one would fault your choice but you'll find that a split load single phase board and three pole isolator is a lot cheaper. Save yourself a few quid for down the pub!

gazj82 · Oct 17, 2013

D Skelton said:
It's your call and no one would fault your choice but you'll find that a split load single phase board and three pole isolator is a lot cheaper. Save yourself a few quid for down the pub!

I didn't get what you mean the first time round, then this post made it just click. That is an excellent idea and much better than two boards

I had visions of double pole busbar for some reason. On a side note I have installed a merlin gerin double pole busbar board on a 110v system before many years ago when I was an apprentice. Not sure if they still exist or what there voltage rating was?

Darkwood · Oct 18, 2013

You can build your own 2 tier board and mark as necessary. A few manufacturers sell design and build parts for your own set-up... last one i did was a 2 tier board with on peak at top and off peak along bottom.

D Skelton · Oct 18, 2013

Similar to this:

[ElectriciansForums.net] Do split phase boards exist?

T'was me' last up 'n down

Brightspark2 · Oct 21, 2013

darkwood said:
You can build your own 2 tier board and mark as necessary. A few manufacturers sell design and build parts for your own set-up... last one i did was a 2 tier board with on peak at top and off peak along bottom.

Yes, used hager ones like this in the past, build it up yourself.

Although it wasnt for this scenario...

Brightspark2 · Oct 21, 2013

D Skelton said:
Similar to this:

View attachment 21031

T'was me' last up 'n down

Very nice :smiley2:

sledgehammer · Oct 22, 2013

The stupid thing is that the cut out and meter ratings are only 400/415v. So why do we worry? If they give you 480v but just use there ordinary set up. I've looked but not found any special precautions or guide lines to follow.

P.s. Split is common around areas I work but some guys never see it and say "are you sure??" As if you're seeing things.

Do split phase boards exist?

gazj82

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D Skelton

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Marvo

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gazj82

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netblindpaul

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D Skelton

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gazj82

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D Skelton

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gazj82

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Darkwood

D Skelton

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Brightspark2

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Brightspark2

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sledgehammer

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