EWH and AHU Disc's in small mech closets

[Ragin Cajun]

Got the following comment from a plans reviewer on some apartments we are doing.

"Proper working clearance will be required for all disconnects per section 110.26 of the 2008 National Electric Code. The specific concern are the disconnects for the Air Handler and Water Heater disconnects in the mechanical closets for all units."


The EWH and AHU are in a small closet. This is the first time this "issue" has been raised. I don't know where else they could be located!


Suggestions?

Note, what is done when an AHU is above a lay-in ceiling?


Thanks,


RC

 

[maghazadeh]

Got the following comment from a plans reviewer on some apartments we are doing.

"Proper working clearance will be required for all disconnects per section 110.26 of the 2008 National Electric Code. The specific concern are the disconnects for the Air Handler and Water Heater disconnects in the mechanical closets for all units."

The EWH and AHU are in a small closet. This is the first time this "issue" has been raised. I don't know where else they could be located!


Suggestions?

Note, what is done when an AHU is above a lay-in ceiling?


Thanks,


RC

As long as you maintain 30" width working space for both disconnects you are in complaince [base on sec. 110.26 (A)(2), "specifies that the width of the working space in front of electrical equipment shall be the width of equipment or 30" whichever is greater".], assuming you have 36" in front, and 6' height working space.
Now if space is limited, try install both disconnects side by side, in this case both needs 30" width, not 30" for each disco.

Suggestions?

Note, what is done when an AHU is above a lay-in ceiling?

This one has been posted before in here, I believe above T-bar / lay-in ceiling is exception since space in limited by the grid 2'x2' or 2'x4'. I personally try not to use fusable disconnects above T-bar ceiling, mostly I use toggle switch as a disconnecting means.

 

[Ragin Cajun]

How often is the space rule "violated' when the AHU is in the attic or in the crawl space?

Is the inspector going to tell you to move the unit???

I'm obviously having a hard time with this one!


RC

 

[iwire]

Got the following comment from a plans reviewer on some apartments we are doing.

"Proper working clearance will be required for all disconnects per section 110.26 of the 2008 National Electric Code. The specific concern are the disconnects for the Air Handler and Water Heater disconnects in the mechanical closets for all units."


The EWH and AHU are in a small closet. This is the first time this "issue" has been raised. I don't know where else they could be located!


Suggestions?

Note, what is done when an AHU is above a lay-in ceiling?


Thanks,


RC

I think it is an odd call.

I would try to eliminate the disconnects at the units altogether and use a lock off means at the breaker as the NEC allows.

 

[steve66]

I think it is an odd call.

I would try to eliminate the disconnects at the units altogether and use a lock off means at the breaker as the NEC allows.

Wow - that makes sense from a code standpoint, but is the inspector really doing anyone any favors if this is what it comes too?

That's really going to make it a lot harder to troubleshoot any problems with the AHU's. The installation will loose both a disconnect at the unit, and a convinent place to check for voltage at the unit.

 

[iwire]

Just remembered that AHUs units have motors, a remote lock off may not be an option for them.

 

[jwelectric]

I have a problem with this 110.26 rule and applying it to an equipment servicing disconnect.

In the body of the text of 110.26(A)(1) it makes the following statement;
?likely to require examination, adjustment, servicing, or maintenance while energized?

If this circuit is protected at the panel with overcurrent why would anyone need to do anything to that disconnect while energized including testing for voltage?
As others have pointed out this requirement is not enforced where the equipment is in the crawl space of either the underside or attic of a building or above a lay-in ceiling.

In my opinion the working space is not required for the equipment servicing disconnect as there is a way to de-energize the circuit.

 

[iwire]

I have a problem with this 110.26 rule and applying it to an equipment servicing disconnect.

In the body of the text of 110.26(A)(1) it makes the following statement;
?likely to require examination, adjustment, servicing, or maintenance while energized?

If this circuit is protected at the panel with overcurrent why would anyone need to do anything to that disconnect while energized including testing for voltage?
As others have pointed out this requirement is not enforced where the equipment is in the crawl space of either the underside or attic of a building or above a lay-in ceiling.

In my opinion the working space is not required for the equipment servicing disconnect as there is a way to de-energize the circuit.

So you have no problem with locating disconnects behind an outdoor HVAC unit?

 

[augie47]

I have a problem with this 110.26 rule and applying it to an equipment servicing disconnect.

In the body of the text of 110.26(A)(1) it makes the following statement;
?likely to require examination, adjustment, servicing, or maintenance while energized?

If this circuit is protected at the panel with overcurrent why would anyone need to do anything to that disconnect while energized including testing for voltage?
As others have pointed out this requirement is not enforced where the equipment is in the crawl space of either the underside or attic of a building or above a lay-in ceiling.

In my opinion the working space is not required for the equipment servicing disconnect as there is a way to de-energize the circuit.

Around here it fairly common to perform voltage and current checks at the local disconnect (usually the most readily accessible to connections). We enforce 110.26

 

[jwelectric]

So you have no problem with locating disconnects behind an outdoor HVAC unit?

No I have no problem what so ever as long as there is a disconnect ahead of the one at the unit

 

[jwelectric]

Around here it fairly common to perform voltage and current checks at the local disconnect (usually the most readily accessible to connections). We enforce 110.26

How do you handle crawl spaces?

 

[Dennis Alwon]

We are not talking preference here but code. Sure I try like heck to get every disconnect so that is not behind a a/c unit. When this question was asked at the yearly meeting in Raleigh with 7 members of the cmp, the answer was that 110.26 applies to the disco. When I asked how that worked in crawl spaces and in suspended ceilings they look baffled. I don't see an a/c diso as needing service unless there were fuses in it.

 

[augie47]

How do you handle crawl spaces?

Pretty much the same. 110.26(A)(1) and (A)(2). Only difference in normally headroom and 110.26(E) does not apply to disconnects,
I won't say that most inspectors won't cut a little slack, but for the most part by the book.
A man testing for voltage in a damp, confined crawl space needs all the "safety" he can get .

 

[jwelectric]

Let?s look closely at 110.26

110.26 Spaces About Electrical Equipment.

Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.

1. Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.

(3) Height of Working Space. The work space shall be clear and extend from the grade, floor, or platform to a height of 2.0 m (6? ft) or the height of the equipment, whichever is greater. Within the height requirements of this section, other equipment that is associated with the electrical installation and is located above or below the electrical equipment shall be permitted to extend not more than 150 mm (6 in.) beyond the front of the electrical equipment.

So what you are saying is that you enforce part of this section but not the entire section.

 

[augie47]

Let?s look closely at 110.26


So what you are saying is that you enforce part of this section but not the entire section.

Unsure what you are quoting from. All I have to go by is the '08 NEC currently being used in my
jurisdiction:

110.26:
(E) Headroom. The minimum headroom of working spaces about service equipment, switchboards, panelboards, or motor control centers shall be 2.0 m (6? ft). Where the electrical equipment exceeds 2.0 m (6? ft) in height, the minimum headroom shall not be less than the height of the equipment.
Exception: In existing dwelling units, service equipment or panelboards that do not exceed 200 amperes shall be permitted in spaces where the headroom is less than 2.0 m (6? ft).

 

[jwelectric]

Unsure what you are quoting from. All I have to go by is the '08 NEC currently being used in my
jurisdiction:

The 2011 NEC Plus.

There is a change in the 2011 that brings "E" into A3 where it should have been for the past few years. I think that by making this move inspectors will learn that the disconnects installed for servicing is not what this section is addressing and use a little common sense in the fact that the overcurrent device where this circuit is being supplied from is all that is needed to keep someone from working on the disconnect while it is energized. There is no requirement to test voltages at this disconnect. This would be by choice only.

In your '08 code it states in A3;
(3) Height of Working Space. The work space shall be clear and extend from the grade, floor, or platform to the height required by 110.26(E). Within the height requirements of this section, other equipment that is associated with the electrical installation and is located above or below the electrical equipment shall be permitted to extend not more than 150 mm (6 in.) beyond the front of the electrical equipment

I says that the height found in 110.26(E) shall be. It does not say to go to 110.26(E) and do what it says there.

 

[augie47]

The 2011 NEC Plus.



I says that the height found in 110.26(E) shall be. It does not say to go to 110.26(E) and do what it says there.

That is exactly what it says to me {go to (E) to determine headroom required}, but I am not going to argue the point.
The method i use is the one adopted by a dozen inspectors in this area and approved by our AHJ.
So it is written, so it shall be here !

 

[don_resqcapt19]

I have a problem with this 110.26 rule and applying it to an equipment servicing disconnect.

In the body of the text of 110.26(A)(1) it makes the following statement;
“likely to require examination, adjustment, servicing, or maintenance while energized”

If this circuit is protected at the panel with overcurrent why would anyone need to do anything to that disconnect while energized including testing for voltage?

That would be the very first step for someone troubleshooting non-working equipment with a local disconnect. Why would you want to check for voltage at any other point?

As others have pointed out this requirement is not enforced where the equipment is in the crawl space of either the underside or attic of a building or above a lay-in ceiling.

In my opinion the working space is not required for the equipment servicing disconnect as there is a way to de-energize the circuit.

The way the code is written now very clearly requires 110.26(A) spaces for all equipment that is likely to be worked on while energized. In my opinion, that is ALL electrical equipment. The fact that there is a way to de-energize the circuit on the line side of the disconnect has no effect on the application of this rule. This rule only hinges on "if someone is likely to work on it while it is energized". Nothing else even enters into this rule based on the current wording.

The real problem is the CMP's refusal to accept reasonable proposals to make this a workable code section. As you and others have pointed out, it is an often ignored section and it needs work.

 

[jwelectric]

It doesn?t make any difference because as soon as you all adopt the 2011 the argument goes out the window anyway.

Even in the 2008 edition A3 is addressing head room for the same equipment that A1 and A2 is addressing.
If you are going to require the working space for equipment in a crawl space then that same equipment will require the headroom. It requires it now but it is crystal clear in 2011 cycle.

 

[jwelectric]

That would be the very first step for someone troubleshooting non-working equipment with a local disconnect. Why would you want to check for voltage at any other point?.

I know that different people have different ways of doing things but if I was checking voltages I would start at the last place I terminated the conductors and that would be at the appliance or equipment. I do realize that a lot of people will start in the middle but why they do that is beyond my comprehension.

I have checked voltages in light fixtures, junction boxes, in the control panels of the equipment such as dryers, ranges and water heaters. Are the removable panels on these appliances required to have the working spaces also?

I remember once having an underground feeder that wasn?t working so we dug up the conductors in places to test. Was we supposed to open a hole that was 30 by 36 inches to do this testing?

In my most honest opinion I think that some try to make this harder than what it is intended to be. Where to do voltage test is a choice each person makes on their own.