I have a residential rewiring job that would be greatly simplified if I could install a 120/240 branch circuit panelboard in the unfinished attic. The location would comply with the depth, width, headroom and illumination requirements of 110-26. However, the attic is entered by a set of pull-down stairs. I'm not sure these constitute a "permanent ladder" under 110-33(b). Opinions? Any other Code requirements I've missed?
Panelboard in Residential Attic?
- Thread starter kenjsil
- Start date
- Status
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Panelboard in Residential Attic?
110.33(B) is for an "Over 600 Volt" application.
What you described appears to meet 240.24.
110.33(B) is for an "Over 600 Volt" application.
What you described appears to meet 240.24.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Panelboard in Residential Attic?
I am not so sure, Bob. The wording of the definition of ?Readily Accessible? (which is cited within 240.24) excludes the use of ?portable ladders.? I might be willing to concede that a ?pull down ladder? is not ?portable,? in the sense of the definition. But it seems to me that an AHJ might not agree.
Here?s another consideration: It is a good bet that this panel will power loads on the main floor(s) of the residence. If a person had to turn off a load ?in a hurry,? they would have to pull down the ladder, climb the stairs, find the right breaker, and turn it off, during all of which time they are in a state of elevated emotions. I don?t think that running up a ladder while being concerned that the house might burn down from an arcing load is safe. It might even be the reason that an AHJ could rule that the overcurrent devices are not readily accessible, and thereby disallow the installation.
I don?t have a strong feeling on this one. But I would suggest looking hard for another way to do this job.
I am not so sure, Bob. The wording of the definition of ?Readily Accessible? (which is cited within 240.24) excludes the use of ?portable ladders.? I might be willing to concede that a ?pull down ladder? is not ?portable,? in the sense of the definition. But it seems to me that an AHJ might not agree.
Here?s another consideration: It is a good bet that this panel will power loads on the main floor(s) of the residence. If a person had to turn off a load ?in a hurry,? they would have to pull down the ladder, climb the stairs, find the right breaker, and turn it off, during all of which time they are in a state of elevated emotions. I don?t think that running up a ladder while being concerned that the house might burn down from an arcing load is safe. It might even be the reason that an AHJ could rule that the overcurrent devices are not readily accessible, and thereby disallow the installation.
I don?t have a strong feeling on this one. But I would suggest looking hard for another way to do this job.
Re: Panelboard in Residential Attic?
Bob -
Thank you for the correction on 110-33 (I missed the Over 600 Volts heading).
Charlie B -
Thank you for reminding me of 240-24 and definitions. I think your reasoning is compelling. The existing installation isn't much better - an exterior panel located around the side of the house down some concrete stairs - not an easy place to get to at night. Obviously, I would like my work to improve on this, so I will look for another location for the panel.
Bob -
Thank you for the correction on 110-33 (I missed the Over 600 Volts heading).
Charlie B -
Thank you for reminding me of 240-24 and definitions. I think your reasoning is compelling. The existing installation isn't much better - an exterior panel located around the side of the house down some concrete stairs - not an easy place to get to at night. Obviously, I would like my work to improve on this, so I will look for another location for the panel.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Panelboard in Residential Attic?
Yeah, I thought about that and if it were a service I?d reject it based on 230.70(A)(1); but it wasn?t described as a service.
?Accessible? is more restrictive in some ways than ?readily accessible.? I?m permitted to ?guard?by locked doors, elevation, or other effective means a ?readily accessible? location but not an ?accessible? one. The problem with ?readily accessible? is that ?quickly? is undefined.
My opinion is that the occupant or first responders would more likely operate the service main than hunt for the attic panel. The service distribution panel directory would note the location of the sub-panel.
My opinion isn't that strong either; I'd probably have more "warm fuzzies" with a different solution too.
Yeah, I thought about that and if it were a service I?d reject it based on 230.70(A)(1); but it wasn?t described as a service.
?Accessible? is more restrictive in some ways than ?readily accessible.? I?m permitted to ?guard?by locked doors, elevation, or other effective means a ?readily accessible? location but not an ?accessible? one. The problem with ?readily accessible? is that ?quickly? is undefined.
My opinion is that the occupant or first responders would more likely operate the service main than hunt for the attic panel. The service distribution panel directory would note the location of the sub-panel.
My opinion isn't that strong either; I'd probably have more "warm fuzzies" with a different solution too.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Panelboard in Residential Attic?
I agree. In fact, that is why I keep a flashlight in the general area of my main panel at home.
highkvoltage
Senior Member
Re: Panelboard in Residential Attic?
charlie,I mounted an battery back up sconce light to shine on my panel. If a breaker trips no problem and I never have to worry about batteries. I also always mount them in homes I wire and tie it into the lighting circuit for the basement. If the lights go out the kids aren't in the dark to find the steps.
charlie,I mounted an battery back up sconce light to shine on my panel. If a breaker trips no problem and I never have to worry about batteries. I also always mount them in homes I wire and tie it into the lighting circuit for the basement. If the lights go out the kids aren't in the dark to find the steps.
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