Question on defining clear working space over 600 volts

[jerryjtb]

I am looking to clarify a question on working spaces about electrical equipment over 600 volts.

<600 volts:

1910.303(g)(1)(i) states working space for equipment likely to require examination, adjustment, servicing or maintenance while energized shall comply with the following dimensions, except as required or permitted elsewhere in this subpart. Paragraph (A) refers you to Table S-1.

>600 volts:

1910.303(h) (5)(i) states Except as elsewhere required or permitted in this subpart, the minimum clear working space in the direction of access to live parts of electrical equipment may not be less than specified in table S-2.

Distances shall be measures from the live parts, if they are exposed, or from the enclosure front or opening, if they are enclosed.

Here is where my question is? Are the working distances still required if you can de-energize the > 600 volt equipment before testing and servicing? It would seem that there is no hazard if the voltages are enclosed or de-energized but the statement would seem to indicate the working distances are required either way.

 

[muskiedog]

It must always be maintained as a clear space.

 

[charlie b]

It is not a matter of whether the power can be turned off. It is a matter of whether the equipment is ?likely to require? work while it is live. I suspect that most people (notably including those who have authority over electrical installations) would look at things in the opposite manner to your suggestion. They would say, ?prove to me that it can not and never will be worked on live, and show me how this will be true forever, even if someone else takes over ownership of the building,? or something along those lines. The net result is that all panels, switchboards, and switchgear are going to fall under the rules for working clearance.

 

[zog]

If the system has been placed in an "Electrically safe work condition" then the boundaries do not apply. That means Isolated, LOTO, verfiied deenergized with proper device, and personal protective grounds applied that are reated for the available fault duty.

The distances you are looking at are being replaced by the minimum approach distances found in the NFPA 70E. Limited, Restricted, and Prohibited approach boundaries.

 

[zog]

Ok are we talking about the minimum appproach distances in table s-2 or are we talking about keeping the area clear of storage materials.

If you are talking about the distances for people to stay away then I stand behind my previous post. If your question is about keeping an area clear (Accessable) then never mind my post and follow Charlies advice.

 

[jerryjtb]

More information on the clear distances

More information on the clear distances

The electrical test equipment in question may have up to 50 kV DC @ 5 Amps under normal working conditions. Placement of the equipment is such that there is only three to four feet clearance side to side, three feet back to wall and they have removable front, side and rear panels for testing and servicing. Does powering down and performing lockouts preclude the S-2 distances?