Tap Rules

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Chamuit

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
I ran across a commerical job Friday where the existing panel only has 4 available spaces left in it to feed 4 (four) 240V 15A air handlers. Can't legally thin the breakers according to the instructions on the panel cover. There isn't anywhere to set a new sub-panel.

One guy suggested to put a sub-panel in the (unfinished) attic. Another suggested running a 60 amp circuit up to the attic and tap off to each unit. I'm thinking since I don't know what the lengths will be that I'd have a problem. Are there limits to the number of taps?

Can anyone help a little here. I just don't do this ever. Better ideas, even?
 
Chamuit

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
Smart $ said:
Perhaps.

http://www.google.com/products?sourceid=navclient&ie=UTF-8&rlz=1T4ADBF_enUS323US254&q=bq215215

PS: Just a friendly reminder. Check to see whether or not adding these circuits will overload the panel.
Click to expand...

41zDp%2BYP5%2BL._SL500_AA300_.jpg


No quads or thins can be used. Same loads, pretty much. Going from gas furnaces to straight air-handlers.
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
Chamuit said:
41zDp%2BYP5%2BL._SL500_AA300_.jpg


No quads or thins can be used. Same loads, pretty much. Going from gas furnaces to straight air-handlers.
Click to expand...



You posted that picture, does that mean you have a CH? If there's 6 & 1/2 feet in the attic, run a feeder from panel to attic. Set a 4 space panel, and put two double poles in it to each air handler. Set your sub panel within sight and inside of 50 ft from units
 
X

xformer

Senior Member
Location
Dallas, Tx
Occupation
Master Electrician
mcclary's electrical said:
You posted that picture, does that mean you have a CH? If there's 6 & 1/2 feet in the attic, run a feeder from panel to attic. Set a 4 space panel, and put two double poles in it to each air handler. Set your sub panel within sight and inside of 50 ft from units
Click to expand...

Does CH refer to Cuttler- Hammer ??
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
mcclary's electrical said:
You posted that picture, does that mean you have a CH? If there's 6 & 1/2 feet in the attic, run a feeder from panel to attic. Set a 4 space panel, and put two double poles in it to each air handler. Set your sub panel within sight and inside of 50 ft from units
Click to expand...
Why not an 8-space w/four 2p's?
 
Smart $

Smart $

Esteemed Member
Location
Ohio
mcclary's electrical said:
Strictly for convenience, you could. But if they paid me to wire ONLY THOSE air handlers, I would size my feeder, and panel, for ONLY THOSE. You can get a 4 space panel cheap. If this was my own house, 8 space or more.
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I believe Larry was referring to the need for 2-pole breakers. 4 circuits = 8 spaces for full size breakers.
 
C

ctmike

Senior Member
can you put a panel in an attic ? This question came up at a ceu class this winter. What would be the the ambient temp in the attic and the rating of the equipment
 
Chamuit

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
McClary's Electrical said:
You posted that picture, does that mean you have a CH? If there's 6 & 1/2 feet in the attic, run a feeder from panel to attic. Set a 4 space panel, and put two double poles in it to each air handler. Set your sub panel within sight and inside of 50 ft from units
Click to expand...
The picture was to show the style of panel I would be feeding from.

Smart $ said:
I read you loud and clear... but I'm left wondering why. Spec's? Panel configuration?
Click to expand...
There aren't any real specs. Just equivalent loads.

I'd be designing and installing what I want.

There isn't any place left to put a sub-panel inside or outside the building.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
Chamuit said:
...

There aren't any real specs. Just equivalent loads.

I'd be designing and installing what I want.

There isn't any place left to put a sub-panel inside or outside the building.
Click to expand...
How does this response relate to, "No quads or thins can be used." :confused:
 
P

Philip Barr

Member
Location
Minneola Florida
If you go with the tap idea, although I've never done this and most electricians may look at you crosseyed for doing it, code compliant though it may be.
From what I know for branch circuits with taps you can't exceed 50 amps for your circuit wires. But since you load for 15amp devices should be 12 amps or less your circuit shouldn't exceed 48 amps.
Table 210.24, and article 210.19(4) seem to point to a 50 amp circuit with a #6awg run with #12 taps not exceeding 18" long.
May run that by your AHJ first but sounds like a sound installation to me.
On putting panelboards in attics, unless it's a dwelling unit you will be hard pressed to come up with 6-1/2' of headroom 110.26(e). And if you had that you can add a light and switch to your installation 110.26(d). And building codes would also probably require a work platform as well. Rule of thumb IMO...don't put panelboards in attics.
 
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Hameedulla-Ekhlas

Hameedulla-Ekhlas

Senior Member
Location
AFG
Chamuit said:
I ran across a commerical job Friday where the existing panel only has 4 available spaces left in it to feed 4 (four) 240V 15A air handlers. Can't legally thin the breakers according to the instructions on the panel cover. There isn't anywhere to set a new sub-panel.

One guy suggested to put a sub-panel in the (unfinished) attic. Another suggested running a 60 amp circuit up to the attic and tap off to each unit. I'm thinking since I don't know what the lengths will be that I'd have a problem. Are there limits to the number of taps?

Can anyone help a little here. I just don't do this ever. Better ideas, even?
Click to expand...

Sub-panel is good idea.
 
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