220 HVAC disconnect box clearance

[joe tedesco]

Re: 220 HVAC disconnect box clearance

What about this installation? Will the inspector here allow this too?

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Wayne,
On a service call one of the first things many service techs will do is check the voltage at the line side of the disconnect. That is working on the disconnect while energized.
Don

 

[russ]

Re: 220 HVAC disconnect box clearance

Dave,
That's what I've been allowing.

Joe,
Can't say I would allow that one. It definately does not fit the discription of readily accessable.

Russ

 

[jzoll]

Re: 220 HVAC disconnect box clearance

Gentlemen,

Thank you for your replies. I'm very impressed with the level of professional judgement shared beyond the strict quotation of the NEC.

Thanks to all for your comments.

J. Zoll

 

[hurk27]

Re: 220 HVAC disconnect box clearance

Don
So is going under a kitchen sink to stick your wiggy into the receptacle to see why the disposal is not working.
But it too is a disconnect isn't it? A disconnect with a pull out does not have any live (energized) parts even with the pullout removed that you can come into contact with. and where the pullout sticks in is where you can check for voltage with out any exposure to live parts any more than any receptacle will.

The disconnects in Joe's photo are fused disconnect and would require changing the fuses while energized and exposed parts. these would fall under 110.26.as I listed before.

Here is what I'm getting at.
110.26 (A)(1)
Condition 1 ? Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by suitable wood or other insulating materials. Insulated wire or insulated bus-bars operating at not over 300 volts to ground shall not be considered live parts.

As you can see the 3 conditions all require "Exposed Live Parts"

In a pullout disconnect there is no exposed live parts! They are UL listed for use without a dead front. There is no maintenance that can ever be done on these types of disconnects. and if they need to be replaced the manufacture gives explicate instructions to remove all power before working on. so this tells me they are not intended to be serviced while energized.

Here is the info on one of these pullout disconnects:

MilBank U3800 pdf

I also scaned the label into the computer. But I don't have a web page to post it to. but I'll E-Mail it to any one who want's to post it.

[ December 16, 2003, 09:23 PM: Message edited by: hurk27 ]

 

[websparky]

Re: 220 HVAC disconnect box clearance

Hi Wayne,

Here is what the Handbook has to say as a way of understanding the requirement.

110.26 Spaces About Electrical Equipment.
Sufficient access and working space shall be provided and maintained about all electric equipment to permit ready and safe operation and maintenance of such equipment. Enclosures housing electrical apparatus that are controlled by lock and key shall be considered accessible to qualified persons.

Handbook Comentary following the article above.

Key to understanding 110.26 is the division of requirements for spaces about electrical equipment in two separate and distinct categories: working space and dedicated equipment space. Working space generally applies to the protection of the worker, and dedicated equipment space applies to the space reserved for future access to electrical equipment and to protection of the equipment from intrusion by nonelectrical equipment. The performance requirements for all spaces about electrical equipment are set forth in the first sentence. Storage of materials that blocks access or prevents safe work practices must be avoided at all times.

 

[hurk27]

Re: 220 HVAC disconnect box clearance

But if we applied that idea to all electrical equipment. we would have to keep a space around everything! Lights, receptacle's, switch's. the list could include anything that uses electricity. but since these devices have been rendered safe by isolating the energized parts from contact by a person. this requirment seem's to only point to devices that might have "exposed live parts" when a person has to work on them while energized. receptacle's are not intended to be worked on while energized, But a voltage test can be safely preformed while it is energized because the terminals are insulated and isolated from contact. So are these pullout disconects.
I guess I need to get UL's 1429 requirment to see what it says to this.

Even the definition of exposed seems to back this also:
Exposed (as applied to live parts). Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to parts that are not suitably guarded, isolated, or insulated.

[ December 16, 2003, 10:20 PM: Message edited by: hurk27 ]

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Wayne,
When the code says "exposed live parts" in 110.26 it really doesn't mean exposed live parts. If it did, there would be no reason for 110.26(A)(1)(c).
As far as this section applying to every electrical installation, it does. It is a very poorly worded section and should be changed. There have been many proposals to clarify exactly what equipment that the rule applies to, but they have been all rejected by the CMP.
Don

 

[charlie b]

Re: 220 HVAC disconnect box clearance

Originally posted by binney: More specific than just 110.26(A), how about 110.26(F)(2)? This would require the clearances regardless of the issue of servicing or maintenance. It states that outdoor equipment SHALL have the CLEARANCES of 110.26(A) the equipment doesn't have to fall under the other requirements of 110.26(A)

I beg leave to disagree. We are talking about a single disconnect switch. I believe that that component does not fall into the requirements of NEC 110.26(F), ?Dedicated Equipment Space.? That article says, ?All switchboards, panelboards, distribution boards, and motor control centers shall be located in dedicated spaces and protected from damage.? A single disconnect switch does not a panelboard make. Therefore, the entire article 110.26(F) does not apply, and you do not get to apply the requirements of the sub-paragraph 110.26(F)(2).

 

[hurk27]

Re: 220 HVAC disconnect box clearance

Don

there would be no reason for 110.26(A)(1)(c).

Panel boards with a dead front would not mater as to work on it you have to remove the dead front. and if this is performed while the panel is live you would have "exposed live parts" Remember this artical is about Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized

I still say there is nothing that you could work on in a pullout disconect "While energized" If any problem happened where it needed repair or replacement the manufactures instruction clearly states to "Remove all power before working on" This message is right on the inside of the cover.
This would mean that there is no need ever to work on it while energized. which is the exact requirment in 110.26 " likely to require examination, adjustment, servicing, or maintenance while energized "

[ December 18, 2003, 03:04 AM: Message edited by: hurk27 ]

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Wayne,
As far as there being live parts, if you are using any type of tool or tester that is in contact with the live parts, you are, per OSHA rules, working on energized equipment.
The rule in 110.26(A)(1)(c) says that the equipment behind you is "exposed live parts" even when the dead front covers are in place.
Don

 

[jimwalker]

Re: 220 HVAC disconnect box clearance

In the real world sparky is sent on service call because the AC man said he has no power at the outside unit.He will open the cover pull the pullout out and remove that dead front and ck for voltage.He should have work space but we all know often there is not enough.Planning on the EC ,AC,and GC could have taken care of this.The print is to scale and shows location.Most of the time the AC man has been there before EC and you know where his unit is going, if not get on that cell phone and call the GC.I respect the inspectors that demand work space here.

 

[iwire]

Re: 220 HVAC disconnect box clearance

Originally posted by don_resqcapt19:
The rule in 110.26(A)(1)(c) says that the equipment behind you is "exposed live parts" even when the dead front covers are in place.
Don

110.26(A)(1)(c)Existing Buildings.
In existing buildings where electrical equipment is being replaced, Condition 2 working clearance shall be permitted between dead-front switchboards, panelboards, or motor control centers located across the aisle from each other where conditions of maintenance and supervision ensure that written procedures have been adopted to prohibit equipment on both sides of the aisle from being open at the same time and qualified persons who are authorized will service the installation.

I am missing what you are saying.

 

[websparky]

Re: 220 HVAC disconnect box clearance

hurk,

You said earlier:

I still say there is nothing that you could work on in a pullout disconect "While energized" If any problem happened where it needed repair or replacement the manufactures instruction clearly states to "Remove all power before working on" This message is right on the inside of the cover.
This would mean that there is no need ever to work on it while energized. which is the exact requirment in 110.26 " likely to require examination, adjustment, servicing, or maintenance while energized "

I looked at your profile and it says you are an electrician.
Really?
If you are an electrician, what type of electrical work do you perform were the power is always turned off to the equipement?

Day in and day out, service electricians across this country (in the real world) work on energized equipement. There are far too many installations that require testing and maintainance while energized.

Yes, I agree with you in spirit. All power should be disconnected before any cover is removed. But this is just not going to happen. This is why we have codes to help all of us understand the liabilities.

If you were to make an error in judgement concerning equipment clearances, wouldn't you rather make sure the next electrician that comes along has a good chance of being safe, rather than saying "Oh, he will turn it off before he works on it"?

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Bob,
I'm sorry. I did not say what I wanted to say in my earlier post.
What I meant to say is that 110.26(A)(1)(c) makes it clear that in new installations the code considers electrical equipment on the opposite side of the aisle to be exposed live parts even when the covers are in place. At the time the rule that is now 110.26(A)(1)(c) was placed into the code, it was an exception to the general work space rule. It still works as an exception because you can only use the "condition 2" work space depth for electrical equipment that is across the aisle from other equipment in existing buildings where existing equipment is being replaced. In new installations, dead front equipment across an aisle requires a "condition 3" work space depth.
Don

 

[iwire]

Re: 220 HVAC disconnect box clearance

Thank you Don, I knew I was just missing what you where trying to get across.

 

[hurk27]

Re: 220 HVAC disconnect box clearance

Don

posted by don :
The rule in 110.26(A)(1)(c) "exposed live parts" even when the dead front covers are in place.
Don

How? When it say's "prohibit equipment on both sides of the aisle from being open at the same time "
If they are meaning "exposed live parts" with the dead front on,Then what are they refering too when they say "Open at the same time? what's open? the dead front? This has no logic if it only meant the outside door/cover.


110.26(A)(1)(c)Existing Buildings.
In existing buildings where electrical equipment is being replaced, Condition 2 working clearance shall be permitted between dead-front switchboards, panelboards, or motor control centers located across the aisle from each other written procedures have been adopted to prohibit equipment on both sides of the aisle from being open at the same time where conditions of maintenance and supervision ensure that and qualified persons who are authorized will service the installation.

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Wayne,
The rule in 110.26(A)(1)(c) acts as an exception to the main rule. By looking at the wording of the "exception" it becomes clear that for new installations of the "aisle" type "condition 3" space is required for "dead front" equipment. Under the specific conditions laid out in the "exception" the code permits an "aisle" type installation using "condition 2" space. If "condition 2" spacing was permitted for "aisle" type installations of "dead front" equipment, there would be no reason for 110.26(A)(1)(c).
Don

 

[don_resqcapt19]

Re: 220 HVAC disconnect box clearance

Day in and day out, service electricians across this country (in the real world) work on energized equipement. There are far too many installations that require testing and maintainance while energized.

Testing is one of the very few times that working on or near exposed live parts is permitted by OSHA. Even when this is permitted, suitable PPE is required. Very few electricians are in compliance with the OSHA rules when testing live electrical equipment.
Don

 

[hurk27]

Re: 220 HVAC disconnect box clearance

Dave

Posted byave I looked at your profile and it says you are an electrician.
Really?

Since 1976.

Day in and day out, service electricians across this country (in the real world) work on energized equipement. There are far too many installations that require testing and maintainance while energized.

Yes I do live in the real world, And I know the practices of alot of electrican's, Even me. But if you go back and read some of my early post you will see that the disconect that I'm talking about does not have any exposed live parts. It don't even have a dead front as it is listed by UL without one. this is because all connections are recessed in plastic and there is no way to come into contac with any thing that is energized by sticking your hand in this typed of disconect. This disconect can be opened by any kid and there is no exposed energized parts this kid could get a shock from. remember there is no dead front to remove so the wires are exposed from where they leave the romex jacket to where they terminate under the lugs but the wire it self is insulated. As far as taking a voltage reading, when the pullout is removed any wiggy or voltage tester that has insulated prongs can be stabed into the plug socket just like the way we test for voltage on a receptacle. but the receptacle for the pullout is recessed so the contacts are not exposed to the touch again just like a duplex receptacle. Since the gut of this disconect is a one piece molded unit the only thing a person could do is remove the wires. I don't know anyone that would try to remove live wires feeding a disconect. although I have heard of this. It would not be something that would normaly be done. and would not be safe in any manner. as I have said before there are disconects that do fall under 110.26 but this disconect don't seem to meet the requirment.

Here again is the web site for this disconect:

Milbank U3800 pdf.

[ December 18, 2003, 07:30 PM: Message edited by: hurk27 ]