3 phase disconnect

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Dexie123

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Is it permissible to take three circuits (110v each) which separate neutrals out of a disconnect to feed three separate loads? This disconnect derives its power from the load side of a bus. The disconnect is fused and each connector is 20 amp and fused properly.

Thank you
 
I agree you can have three single 120 volt circuits all from the same single 3 pole disconnect. Just curious how will you connect the neutrals?
 
infinity said:
It sounds like he will have three separate neutrals into and out of the disconnect so no MWBC.
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All tied to a common neutral though it may be only a few inches long before it connects to the feeder neutral. In many ways the same as if you ran true MWBC to a junction box then split into three separate two wire branches from there.
 
kwired said:
All tied to a common neutral though it may be only a few inches long before it connects to the feeder neutral. In many ways the same as if you ran true MWBC to a junction box then split into three separate two wire branches from there.
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Got that part but I still don't see where he said he has a common neutral. Not saying he doesn't but I don't see that in his description of the installation.
 
kwired said:
All tied to a common neutral though it may be only a few inches long before it connects to the feeder neutral. In many ways the same as if you ran true MWBC to a junction box then split into three separate two wire branches from there.
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No one specifically mentioned the three circuits supply being different phases.
Dexie123 said:
... This disconnect derives its power from the load side of a bus. ...
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infinity said:
Got that part but I still don't see where he said he has a common neutral. Not saying he doesn't but I don't see that in his description of the installation.
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Well I suppose he could have a disconnect with no neutral lugs and the wire nut he mentioned connects the branch neutrals directly to the feeder neutral.
 
Man,,,,, we really need to find something more exciting to do don't we.... :lol:


JAP>
 
It's kind of an odd scenario. An after thought more than likely.

This is a 4 wire disconnect tapped off the main bus of a large MDP. That is a black, red, blue, and white wire to a 3 phase fused disconnect. It was engineered by our head engineer.

You are correct there is only one nuetral. I don't like the idea of having only one nuetral and would prefer to pull a separate one.
 
Dexie123 said:
It's kind of an odd scenario. An after thought more than likely.

This is a 4 wire disconnect tapped off the main bus of a large MDP. That is a black, red, blue, and white wire to a 3 phase fused disconnect. It was engineered by our head engineer.

You are correct there is only one nuetral. I don't like the idea of having only one nuetral and would prefer to pull a separate one.
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You do realize that the whole MDP is fed with one neutral, just like the circuit to the disconnect. There is no reason, performance or safety wise, to pull separate neutrals.
 
ActionDave said:
You do realize that the whole MDP is fed with one neutral, just like the circuit to the disconnect. There is no reason, performance or safety wise, to pull separate neutrals.
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In fact, performance wise it is better to have a single neutral unless the harmonic current is very large.

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