# Intermatic timer and arc faults



## pulpfiction32 (Feb 11, 2007)

Has anyone else had any trouble with in wall timers tripping out arc 

fault breakers. I am with-in the load tolerance of the timer and there 

are no CFL's controlled by it, I called the tech support but they were 

unfamiliar with Arc fault breakers.


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## 480sparky (Feb 1, 2009)

Timers are switches.

Switches turn loads on and off.

Sometimes, arcs are created when the contacts open or close.

Arcs are detected by the AFCI breaker.

AFCI breaker opens.


Solution: Buy new timers.


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## DuMass (Feb 6, 2008)

Are these by chance outdoor lights that are being controlled by the timers? If so they don’t need to be on that AFCI. Same for any outdoor receptacles. 
If this is the case, even if the timer switch is located in a room that requires AFCI protection, according to NEC 210.12[A], the timer switch is not supplying outlets or otherwise serving loads in a room or area where AFCI protection is required, so it doesn't have to be on an AFCI.

I should probably note that this is assuming the timer and outside lighting is supplied by a separate branch circuit and not the same one as the rest of the room.


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## SemiRetiredEL (Nov 24, 2009)

DuMass said:


> Are these by chance outdoor lights that are being controlled by the timers? If so they don’t need to be on that AFCI. Same for any outdoor receptacles.
> If this is the case, even if the timer switch is located in a room that requires AFCI protection, according to NEC 210.12[A], the timer switch is not supplying outlets or otherwise serving loads in a room or area where AFCI protection is required, so it doesn't have to be on an AFCI.
> 
> I should probably note that this is assuming the timer and outside lighting is supplied by a separate branch circuit and not the same one as the rest of the room.


DuMass, I agree outside lights are not required to be on AFCI per 2010 and Art 100 does not mention outlets containing switches but I believe an AHJ would probably have a hard time passing on that technicallity.

Also, it's pretty unlikely you will find a switch location (in a room which requires an AFCI) controlling an outside light that is not being supplied by that same room. 

This of course doesn't help the OP. I suspect the tripping he talks about is due to GFP not arc-fault.


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## DuMass (Feb 6, 2008)

SemiRetiredEL said:


> DuMass, I agree outside lights are not required to be on AFCI per 2010 and Art 100 does not mention outlets containing switches but I believe an AHJ would probably have a hard time passing on that technicallity.
> 
> Also, it's pretty unlikely you will find a switch location (in a room which requires an AFCI) controlling an outside light that is not being supplied by that same room.
> 
> This of course doesn't help the OP. I suspect the tripping he talks about is due to GFP not arc-fault.


I think it should be pretty universally understood by inspectors that a switch is not an outlet. Art 100 defines an outlet as the point on the wiring system at which current is taken to supply utilization equipment. That would be the box where the lighting or receptacle is connected, not the switch location.
I will often run a separate circuit for outside lights and receptacles with a switch for the outside lighting located in a living room or other area where the branch circuit supplying it is required to have AFCI protection. It’s allowed under the NEC and avoids many problems like the OP has described.


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## pulpfiction32 (Feb 11, 2007)

Yes the outside sconces are on the same circuit as the foyer light and 2 foyer receps. I have two in wall timers at the front door one controls the Outside recessed and the other controls the outside sconces. No problem with the breaker before i put the timmers in. I set the timers for 5 pm they came on and 2 hours later the homeowner tunerd on the foyer light and the breaker tripped. With everything on the amp draw is 7.1 So its not over loaded


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## SemiRetiredEL (Nov 24, 2009)

pulpfiction32 said:


> Yes the outside sconces are on the same circuit as the foyer light and 2 foyer receps. I have two in wall timers at the front door one controls the Outside recessed and the other controls the outside sconces. No problem with the breaker before i put the timmers in. I set the timers for 5 pm they came on and 2 hours later the homeowner tunerd on the foyer light and the breaker tripped. With everything on the amp draw is 7.1 So its not over loaded


Do the timers have a neutral wire or just a ground? We're seeing occupancy sensors being recalled (Zenith and most other low end types) being recalled because they return current (very low) on the ground, not the neutral.

If your timer consumes power it could now be called utilization equipment and if it returns current on the ground is now considered a Code violation in some jurisdictions.

The 0.005 ma being returned (similar to an occupancy sensor) adds with any other ground faults and leakage, capacitance and inductance and could possibly trip the 30 ma. GFP section of an AFCI. So, your AFCI is not sensing overload it may be sensing ground fault.

For this reason the 2011 Code now requires a neutral be provided in all switchboxes, even if not needed immediately.


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