Access Around Draw-Out Switchgear

[ed downey]

I am doing a small presentation on the difference between Switchgear & Switchboards for about (30) non-electrical people at my company.
In my research I came across an article by Brian A. Rener in Consulting - Specifying Engineer which states on page two of the attached that "In addition, the clearance in front must take into account the space needed to drawout a breaker while still maintaining the NEC required clearances."

I have read article 110.26 three times this morning and I cannot see where he is getting this information.

Has anyone else ran into this in their use of Draw-out 600V type Switchgear.

Thanks,
Ed

 

[George Stolz]

I haven't looked at the pdf, but doesn't this make sense?

What clearance would be required if the rack being pulled out was 37"?

Maybe I don't have clear pictures in my head of what's being described here. But I thought this was interesting enough to give it a bump.

 

[Pierre C Belarge]

Ed
I do not see as many draw-out type CBs, but I do see them maybe 2 times/month in my inspections. I have never thought about the clearance issues with the CB drawn out. I will have to "noodle" this now to see what I come up with.
The paper does make sense though...

 

[ron]

It is just the authors interpretation. It is not the way I read the code section.
Just imagine the requirement if the situation was a switchboard with a drawout circuit breaker? It could be. The clearance requirements are similar around the footprint of a SWBD and SWGR.

 

[ed downey]

Ron I read the code in the same way that you do. If it is a requirement (which I cannot actually confirm by reading 110.26) that would mean that engineers would need to provide additional access around any draw-out type Switchgear (UL 1558) or Switchboards (UL 891).

I think that once the breaker is drawn out then it is no longer energized and therefore not subject to the clearance requirements.

If anyone else has any enlightening words about this please feel free to speak up.

-Ed

 

[charlie b]

I think that once the breaker is drawn out then it is no longer energized and therefore not subject to the clearance requirements.

I agree. The author is promoting his own views, and is not teaching the code requirements as they are written.

 

[Nick]

I agree, when the breaker is drawn out it is disconnected from the bus and shutters close off the bus stabs. There is no longer proximity to energized parts. It would be difficult to apply the authors interpretation. If you had a typical 15KV line up set parallel to a 480V line up you would need an electrical room 30ft wide with nothing along the walls.