working clearance

[tmkelly1]

I contend that article 110-26 applies to switches, panelboards,etc.. but not to transformers. The code seems to be almost clear on this issue but I can't convince co-workers.
And then the issue of convincing an inspector. Is there something more concrete other than the explanation in the handbook? Or am I wrong. I think the transformer needs sufficient working space but doesn't need to be inspected while energized.

 

[charlie b]

Re: working clearance

I am on the road, without my NEC handy, but I believe the ?phrase that pays? is ?likely to require maintenance, inspection, and other stuff while energized.?

I agree with you, that a transformer would not need stuff done while energized. But within that phrase that pays is the single word that pays, namely ?likely.? That makes the situation open to the interpretation of anyone and everyone. But the only interpretation that matters is the AHJ.

 

[ryan_618]

Re: working clearance

What about infared testing?

 

[luke warmwater]

Re: working clearance

Hi, Ryan.
You must have been down to Kitchens Etc., for the red light special on Left Handed Pot Stirrers.

'Cause that's a good question.

Isn't it usually done from a distance?
Would that matter?

 

[krmelectricbwm]

Re: working clearance

It is not uncommon to check the voltage found at the taps on a transformer (LIVE WORK) while troubleshooting or performing preventative maintenance in a commercial / industrial facility that has had new electrical loads added to the system supplied by the transformer at a later date. It would be nice if the same working clearances were applied by the inspectors in this case. OSHA has very specific requirements for working clearances on transformers, but I believe they are for ones with the primary at 600+ volts. Anyhow, that my opinion on the subject.

 

[don_resqcapt19]

Re: working clearance

This is a code section that is in very bad need of a complete revision. The section is completely subjective as it is now written and it applies to all electrical equipment. It is completely a judgement call by the AHJ with the current language. If you take it to the extreme, the code required kitchen counter receptacles are a violation of the wording in 110.26. There have been many proposals to CMP 1 to clearly define the equipment covered by this section, but they have all been rejected. The wording should be similar to that in 110.16 where the equipment is spelled out.
Back to the original question, as the code is now written, and based on work practices that I have seen, 110.26 does apply to transformers, in my opinion.
Don

 

[don_resqcapt19]

Re: working clearance

tmkelly1,

I contend that article 110-26 applies to switches, panelboards,etc.. but not to transformers. The code seems to be almost clear on this issue ...

What code wording leads you to this conclusion? 110.26 says it applies to "all electrical equipment". Take a look at the Article 100 defintion of "equipment".

Equipment. A general term including material, fittings, devices, appliances, luminaires (fixtures), apparatus, and the like used as a part of, or in connection with, an electrical installation.

Don

 

[lady sparks lover]

Re: working clearance

Originally posted by don_resqcapt19:
Back to the original question, as the code is now written, and based on work practices that I have seen, 110.26 does apply to transformers, in my opinion.
Don

I have to agree with Don.

 

[charlie b]

Re: working clearance

I refer back to my (intentional) misquote of 110.26, in which I will now narrow the ?phrase that pays? to ?likely to require.? Being an engineer, and therefore being highly unlikely to be required to perform any of the listed activities, I can sit back in my ivory tower and claim that live work is never necessary. But then, my livelihood doesn?t require me to deal with owners who want their equipment fixed NOW, and who won?t let you turn off the power.

So I reiterate that it is subjective, and that only the AHJ?s opinion matters. I also agree with Don, that this section is in serious need of clarification.

 

[lady sparks lover]

Re: working clearance

Originally posted by charlie b:

So I reiterate that it is subjective, and that only the AHJ?s opinion matters. I also agree with Don, that this section is in serious need of clarification.

CB, guess what you'll be surprised how AHJs make up their own rules when it come to this.

Just recently the Code official came back with comment on my design stating:

Per 110.26, provide necessary clearances. Please provide a suitable barrier for in front of all electrical equipment, ie. the tranformer and electrical panels.

And yes, I fought this comment because it does not say you have to build a barrier!

 

[websparky]

Re: working clearance

Lady,

CB, guess what you'll be surprised how AHJs make up their own rules when it come to this.

He didn't make it up, he paraphrased this:

110.26 (B) Clear Spaces. Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.

I would have required the same. The working space needs to be guarantied!

 

[iwire]

Re: working clearance

I go back and forth on the working spaces for transformers.

Usually we provide the space but then again 450.13 lays out the accessibility requirements for transformers

450.13 Accessibility.
All transformers and transformer vaults shall be readily accessible to qualified personnel for inspection and maintenance or shall meet the requirements of 450.13(A) or (B).

(A) Open Installations. Dry-type transformers 600 volts, nominal, or less, located in the open on walls, columns, or structures, shall not be required to be readily accessible.

(B) Hollow Space Installations. Dry-type transformers 600 volts, nominal, or less and not exceeding 50 kVA shall be permitted in hollow spaces of buildings not permanently closed in by structure, provided they meet the ventilation requirements of 450.9 and separation from combustible materials requirements of 450.21(A). Transformers so installed shall not be required to be readily accessible.

The Hollow Space Installation part generally means above a suspended ceiling which rules out compliance with 110.26(A)(3) Height of Working Space.

The same can be said for transformers located in the open on walls, columns, or structures most times this will mean the clear work space from grade to equipment is not available.

 

[lady sparks lover]

Re: working clearance

Originally posted by websparky:
Lady,

He didn't make it up, he paraphrased this:

110.26 (B) Clear Spaces. Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.

I would have required the same. The working space needs to be guarantied!

It was an Electrical closest, and was stated on the drawing!

 

[necbuff]

Re: working clearance

The service men in this forum will beg for that working space. 85% of my career has been service. Anyone who has had to troubleshoot and repair anything knows how important this is. Now as an inspector, I require working clearance on most equipment as ya'll know what the code states. If you may have to service it, you need clearances. Not only from a convienience stand point but a saftey view. If you are working on a piece of equipment hot, and believe me sometimes you have to, and you have your leg unknowingly against something grounded and you contact an energized part (something as simple as a faulty tester lead), I'm telling you I've been there, now you have a direct path across your heart and bam, thats all she wrote. Far fetched? I don't think so. Even if you don't "agree" with it, please consider the saftey of the service men. I am not trying to tell nobody their business, But I feel strongly about this and IMO it is the code.

[ August 15, 2004, 11:14 PM: Message edited by: necbuff ]

 

[don_resqcapt19]

Re: working clearance

Ken,

... and you have your leg unknowingly against something grounded and you contact an energized part (something as simple as a faulty tester lead) ...

That should never happen as OSHA requires the use of voltage rated gloves for that type of work.
Don

 

[sandsnow]

Re: working clearance

Originally posted by iwire:
I go back and forth on the working spaces for transformers.

Kind of like loophole in the Code??!!??

Looks like a good job for the correlating committee to work . Reconcile 110.26 with 450.13

btw, What if the XFMR is over 50kva? We have them build a ladder and a platform to it, if the really want it in the ceiling. Or they raise the ceiling so that it is in the open.

 

[tmkelly1]

Re: working clearance

Well it looks like this is quite controversial. So maybe the code isn't clear enough or is clear enough depending on your individual interpetation and or experience. I too have worked on many transformers hot, but just as easily have checked the voltage at the load device.
the handbook could just as easily have included transformers in their explanation.
I too would like sufficient room in front of a transformer, but sometimes it is a battle with owners and architects to get the room.

 

[lady sparks lover]

Re: working clearance

Originally posted by tmkelly1:

I too would like sufficient room in front of a transformer, but sometimes it is a battle with owners and architects to get the room.

I understand that one, for sure...I did some "looking into" on the subject...and the handbook has the explanation as far as clear spaces too. See below:

B) Clear Spaces. Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.

The hanbook explanation:
Section 110.26(B), as well as the rest of 110.26, does not prohibit the placement of panelboards in corridors or passageways. Thus, while the covers of corridor-mounted panelboards are removed for servicing or other work, access to the area around the panelboard should be guarded or limited, to protect unqualified persons using the corridor.

Lady


PS....to all my fellow poster, the handbook is great to me. It explains a lot, because the code can be quite ambiguous at times!