230.71 Disconnect

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jap

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Barriers to me means some sort of isolation, so, the question to me is, why do we need some type of isolation between main breakers?

Not sure.

Is it so if we shut off one main we have some type of isolation from another energized service disconnect that may be in close proximity?

That would be my guess.

JAP>
 
mbrooke

mbrooke

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jap said:
Barriers to me means some sort of isolation, so, the question to me is, why do we need some type of isolation between main breakers?

Not sure.

Is it so if we shut off one main we have some type of isolation from another energized service disconnect that may be in close proximity?

That would be my guess.

JAP>
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Your primaries would still be hot. To which you just mandate boots. If you want both busbars or secondary terminals dead just trip both (or all) mains.

My main concern is residential and light commercial where multiple mains in a single enclosure is the norm.
 
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jap

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Yes the primary will still be hot, but, if in a compartment, the load side of a main wouldn't be close to another service breaker that is still on as it would be if in a MLO panel with breakers right next to each other.

I'm curious of the actual reasoning myself.

Just throwing my 2 cents in to see if I'm anywhere close to the actual reason.



JAP>
 
mbrooke

mbrooke

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jap said:
Yes the primary will still be hot, but, if in a compartment, the load side of a main wouldn't be close to another service breaker that is still on as it would be if in a MLO panel with breakers right next to each other.

I'm curious of the actual reasoning myself.

Just throwing my 2 cents in to see if I'm anywhere close to the actual reason.



JAP>
Click to expand...


There are meter mains with just two mains in them. Still, trip both breakers if you want to be safe.
 
J

jap

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Yes it is, but, how are compartments going to make this any more safe?

JAP>
 
J

jap

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Other than shutting down the entire service, how does each Main in its own compartment promote safety?

Or does the rule not have anything to do with safety since if working on partly energized equipment requires certain types of PPE to begin with?

JAP>
 
don_resqcapt19

don_resqcapt19

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The line side insulating barriers are required on all exposed line side energized parts. The separate enclosure eliminates exposure to energized load side parts for other service disconnects if they would be in a common enclosure. With a single disconnection device in the enclosure, there are no live energized parts in the enclosure when the disconnect is open.
 
mbrooke

mbrooke

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don_resqcapt19 said:
The line side insulating barriers are required on all exposed line side energized parts. The separate enclosure eliminates exposure to energized load side parts for other service disconnects if they would be in a common enclosure. With a single disconnection device in the enclosure, there are no live energized parts in the enclosure when the disconnect is open.
Click to expand...

Ok so trip both mains. Or put some boots on both secondaries instead. I don't see the problem this rule claims to solve.
 
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jap

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I'd like to hear the actual reason from the code panel rather than keep guessing as to the why.

Does anyone have the actual reason it's resorting to this?

JAP>
 
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