Three new home concerns

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tonype

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NM cables not tied together, but threaded through I-joist knockouts - bundling?

NM in bathroom cabinet to kickplate heater - should these be in conduit for protection from damage?

Can Square D AFCI breakers (QO) be double-lugged?
 

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tonype said:
NM cables not tied together, but threaded through I-joist knockouts - bundling?

NM in bathroom cabinet to kickplate heater - should these be in conduit for protection from damage?

Can Square D AFCI breakers (QO) be double-lugged?
Click to expand...

Regarding the second and third pictures I personally would have rrun the NM up through a stub of conduit to protect the NM from being damaged by items that may be placed in the cabinet.
Regarding the lugs on the breaker being suitable for 2 wires they most likely are rated as such. But, the breaker should be labeled for use as such!.
 
tonype said:
NM cables not tied together, but threaded through I-joist knockouts - bundling?

NM in bathroom cabinet to kickplate heater - should these be in conduit for protection from damage?

Can Square D AFCI breakers (QO) be double-lugged?
Click to expand...


IMO,

Yes, derating needs to be considered, because they are bundled longer than 24"
Yes, because subject to physical damage.
Probably, need to check with Square-D
 
1. I find this an interesting question and took the liberty of copying your picture to another thread and running a poll on how many folks would consider that bundling.
2. IMO, protection would be required
3. My SquareD catalog shows (2) wires allowed on 15-30 amp breakers and does not differentiate for AFCIs. I do not have an actual breaker to see if it is marked.
 
As far as the kickspace heater goes. I would not hardwire it unless it has a long whip for servicing. One customer I am always pulling it out for cleaning or the one shot thermal going out. It's even on a timer.
 
~ ~ ~ & ~ ~ ~


1. Yes, refer to Section E3605.3, in the `06 IRC.

2. By the Letter of the NEC & the IRC, ...probably.......Most people
give no thought or concern to what they slam up against, or
store underneath the sinks........Your definition of "Subject
to physical damage" may be different than mine though !

3. I would refer to Square D for their manufacturer's requirements.


~ ~ ~ & ~ ~ ~
 
If you look at a QOAF you will see that it is just like a QO breaker in regards to the wire lugs. However, there is a very obvious exception. ONE OF THE HOLES AT THE SCREW HAS BEEN BLOCKED OFF. Why do you suppose they did that? The only way you can double tap a QO is one wire on each side of the screw. No you cannot double tap a Sq D AF. "Wake up America"
 
Cavie said:
If you look at a QOAF you will see that it is just like a QO breaker in regards to the wire lugs. However, there is a very obvious exception. ONE OF THE HOLES AT THE SCREW HAS BEEN BLOCKED OFF. Why do you suppose they did that? The only way you can double tap a QO is one wire on each side of the screw. No you cannot double tap a Sq D AF. "Wake up America"
Click to expand...

"Wake up America" not all of us use QO in general, let alone their AFCIs. I personally have held one in my hand but never looked to see if it could be double lugged. Didn't have a reason to look.
 
tonype said:
NM cables not tied together, but threaded through I-joist knockouts - bundling?

NM in bathroom cabinet to kickplate heater - should these be in conduit for protection from damage?

Can Square D AFCI breakers (QO) be double-lugged?
Click to expand...

Are you asking if they are bundled? I would say they are.

How is this any different than dishwasher wiring under a kitchen sink?

Don't know.
 
Bundling is not the correct term.

from 310.15(B)(3):

(3) Adjustment Factors.
(a) More Than Three Current-Carrying Conductors in a
Raceway or Cable. Where the number of current-carrying
conductors in a raceway or cable exceeds three, or where
single conductors or multiconductor cables are installed
without maintaining spacing for a continuous length longer
than 600 mm (24 in.) and are not installed in raceways, the
allowable ampacity of each conductor shall be reduced as
shown in Table 310.15(B)(3)(a). Each current-carrying conductor
of a paralleled set of conductors shall be counted as
a current-carrying conductor.
Click to expand...

By calling it "bundling" it gives many the impression there must be cable ties or similar devices holding those conductors or cables in a "bundle" but the wording in 310.15(B)(3)(a) doesn't use the word "bundling" instead is more generally described as any situation where conductors/cables are in close proximity with no maintained spacing to help with cooling effects.

I suppose one may have a valid argument if you made an obvious attempt to pull those cables apart between each joist, but with no attempt of separation at all they must comply with the adjustment requirements IMO.
 
Cavie said:
If you look at a QOAF you will see that it is just like a QO breaker in regards to the wire lugs. However, there is a very obvious exception. ONE OF THE HOLES AT THE SCREW HAS BEEN BLOCKED OFF. Why do you suppose they did that? The only way you can double tap a QO is one wire on each side of the screw. No you cannot double tap a Sq D AF. "Wake up America"
Click to expand...
I thought I was clear with my reply.

Is Earl Pits still on the radio?
 
how much distance between cables is required to "maintain spacing"? It appears to me that there is some space between at least some of the cables in the bundles in the picture.
 
petersonra said:
how much distance between cables is required to "maintain spacing"? It appears to me that there is some space between at least some of the cables in the bundles in the picture.
Click to expand...
I have to say that it can be a judgement call, but just how many cables can we pull through the same set of holes bored in the framing before we decide it is too hard to consider any spacing being adequately maintained?

Years ago the place I worked for when we did new houses we usually drilled about a 2.5 inch hole and ran however many cables we needed in it, seldom ever needed a second set of holes. Now I still kind of think the load diversity factor of most dwelling circuits still doesn't contribute to excessive heating, but that is a different issue. I now drill only 3/4 - 1 inch holes and usually several sets when close to the panel and only install 9 or less current carrying conductors in whatever combination of cables end up being installed in each hole. If you put many more cables then that in there how do you ensure the ones in the center of the group have adequate spacing around them to dissipate heat? The outer ones may not have enough spacing but at least have more surface exposure to free air.
 
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