AHU disconnects

Status
Not open for further replies.
Jim W in Tampa

Jim W in Tampa

Senior Member
Location
Tampa Florida
Here is situation,off hallway is a 4 ft by 4 ft room with door and with main panel.Just past this small electric room is a normal door to a 3 foot by 4 ft AHU closet.Door to ahu swings into the panel and blocks all but 1 inch of panel from view if door is open to service the ahu.Can a breaker in the panel be used as the disconnect ?
 
I would say yes noone is likely to close the door on the person doing work on the AHu and turn on the breaker without the person doing the work on the AHU knowing it.

do the plans show a disconect by the AHU

does the AHU data plate say Max breaker size or does it say Max fuse size or does it say Max fuse or breaker size If it says Max fuse size without the OR in there it needs a fusable disconect.

check with the inspector and see what he thinks

that being my opinion the inspector has the final say.
 
marinesgt0411 said:
I would say yes noone is likely to close the door on the person doing work on the AHu and turn on the breaker without the person doing the work on the AHU knowing it.

do the plans show a disconect by the AHU

does the AHU data plate say Max breaker size or does it say Max fuse size or does it say Max fuse or breaker size If it says Max fuse size without the OR in there it needs a fusable disconect.

check with the inspector and see what he thinks

that being my opinion the inspector has the final say.
Click to expand...
All else would be fine sept for the insite part.Plans did not show disconnect.
 
that is where it gets tricky you might argue because you can still see 1 inch of the panel cover with door open it is still within sight.

do not have my codebook handy what is the exact wording of the deffinition of "within sight of"
 
My opinion is that the intent is that nobody can approach the panel out of sight of the service-person. I'd say this intent is met by sheer proximity, door or not.
 
LarryFine said:
My opinion is that the intent is that nobody can approach the panel out of sight of the service-person. I'd say this intent is met by sheer proximity, door or not.
Click to expand...
If the wording was differant i would agree.Do i think it would be safe yes.This is not something that normally happens but because of direction od swing it causes a bit of mud.Intent and wording are 2 seperate things.
 
Hi Jim,
If you are concerned, why not just install disconnect by ahu? If you don't want to, I'd check with ahj. It doesn't seem to me to follow the letter of the law. I do think it would be safe.:)
 
I agree with Larry, and would pass this installation. For literal interpretation, I guess I'd say the disconnecting means is not within sight.
 
Jim W in Tampa said:
Here is situation,off hallway is a 4 ft by 4 ft room with door and with main panel.Just past this small electric room is a normal door to a 3 foot by 4 ft AHU closet.Door to ahu swings into the panel and blocks all but 1 inch of panel from view if door is open to service the ahu.Can a breaker in the panel be used as the disconnect ?
Click to expand...

Can you see the breaker itself? If so, I think you can make a good argument it is "in sight". If you can't see the breaker with the door open, then no.

In Sight From (Within Sight From, Within Sight).
Where this Code specifies that one equipment shall be “in
sight from,” “within sight from,” or “within sight,” and so
forth, of another equipment, the specified equipment is to
be visible and not more than 15 m (50 ft) distant from the
other.

Otherwise you would have all kinds of ridiculous issues like someone walking by it blocking a view to it for a few seconds constitutes not "in sight". If the PB has a door to it that might be closed does that mean it is not "in sight" unless the door is removed?

But I am not so sure this kind of thing should be decided by what you can get away with. Adding a disconnect switch inside the AHU closet at the time of install would not add a whole lot to the cost of the project. A three phase non-fused IEC disconnect switch can be purchased for $20 in small sizes.
 
Last edited:
Status
Not open for further replies.
Top