Refrigerator causes circuit to momentarily dim

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Old 04-25-10, 04:16 AM
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Refrigerator causes circuit to momentarily dim

I added an outlet to an existing circuit that previously supplied the receptacles in my living room and dining room and the ceiling lights in the kitchen. This new outlet is in my tall crawl space and I plugged a spare refrigerator into this outlet. Now whenever the refrigerator turns on, it causes the kitchen ceiling lights to dim momentarily. Is this an indication of a major problem? Incidentally, the new outlet was supplied with 12 gauge wire whereas the original circuit had only 14 gauge wire. Is there a problem using 12 gauge wire for this?
 
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Old 04-25-10, 05:29 AM
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The dimming is basically caused by the large amp draw that the fridge uses to start up. That large draw, pulls voltage down, momentarily, thus lights or anything on same circuit will experience a reduction in supply voltage momentarily, thus, the dimming. As far as using 12 Ga, instead of 14ga., is actually better, seeing how it is heavier gauge, and handles large draw better. With that said, just be sure that any receptacles on that 12 gauge wire is rated to handle, 20amps, or whatever size breaker you have it connected to in breaker panel. For example: The 12 ga. wire is rated to handle 20amps, but if you have a 20amp breaker in box powering that cable, you need to be sure the receptacle is rated for 20amps as well. Stick with 15amp, breaker, and 15 amp receptacle, and you'll be ok. Also, make sure that the breaker is rated as low as the weakest circuit as well, which is likely 15amp. I take it you just wired in to an existing junction box, where all those connections are. Would it be a lot of work to run that fridge circuit back to breaker panel? If those lights are standard, not a big deal, but constant voltage drops, even momentarily/occasionally , I believe is hard on the ballast of the florescent lights.
 
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Old 04-25-10, 06:07 AM
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In the US nnless you only have one physical spot to insert a plug on the circuit you can use 15 amp receptacles on a 20 amp circuit. A standard duplex receptacle is two spots. A 15 amp rated device is still rated for 20 amp through capacity.

The other issue is why you have so much on that circuit. The NEC has required the dining room and kitchen receptacles to be on 20 amp circuits for quite a while. That circuit should not have lighting or be shared outside of the kitchen/dining rooms.
 
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Old 04-26-10, 10:20 AM
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The breaker is a 15 amp breaker, the wiring is 14 gauge except for this 12 ft of 12 gauge. This spur is coming from a dead end junction box on which is mounted an incandescent light bulb fixture for the crawl space. This is one of those old fashioned, bare-bulb fixtures with a pull chain switch. For all I know, this crawl space light may not be the end of radial circuit but may be a spur itself. Would that be a problem?

The original ceiling lights on this circuit were a fluorescent fixture and a pendant lamp with something like a 100 watt bulb in it. Now there are seven 65 watt recessed lights in the ceiling and a pendant lamp with five 60-watt bulbs in it. There are no kitchen receptacles on this circuit--only living room and dining room receptacles which supply a few small lamps during my typical usage.

Another new circuit has been installed from my breaker box which has a 20 amp breaker and 12 gauge wire running in the crawl space. It supplies only one outlet, to which is a dedicated microwave oven (1200 watts) and a 24 V DC transformer for a low voltage system. Could I install a junction box in the middle of this run to supply the crawl space refrigerator receptacle? Or must I fish the cable up to the interior outlet where the microwave plugs in.
 
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Old 04-26-10, 11:05 AM
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The wire probably doesn't have enough slack to splice in the middle so you will need to use two Jboxes about a foot apart with a short length of new #12 cable between them. You can come off either box for the refer receptacle.
Could I install a junction box in the middle of this run
 
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Old 04-26-10, 11:06 AM
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Dining room receptacle are to be fed from the kitchen's small appliance branch circuits. This is to supply buffet warmers, crock pots, turkey roasters and the like. I personally think this is ridiculous but "they" never asked me.
Another new circuit has been installed from my breaker box which has a 20 amp breaker and 12 gauge wire running in the crawl space. It supplies only one outlet, to which is a dedicated microwave oven (1200 watts) and a 24 V DC transformer for a low voltage system. Could I install a junction box in the middle of this run to supply the crawl space refrigerator receptacle? Or must I fish the cable up to the interior outlet where the microwave plugs in
. Since (by code) you need a minimum of 6 inches of wire from the point it enters a junction box you would need at least a foot of slack in this cable, which I highly doubt you have. There is also the strong possibility that if the refrigerator were to start when the microwave oven was on that the instantaneous motor surge (of the refrigerator) could case the circuit breaker to trip. Add to that the microwave oven should have its own circuit all to itself (if an "installed" rather than counter-top model) and you are asking for trouble. Note also that if the receptacle the microwave oven is plugged into is also accessible from the kitchen counters or is located in a pantry or dining area it is, by definition, a small appliance branch circuit and that would make the low-voltage transformer on the circuit non-code compliant.

I suggest that you run a new circuit from the circuit breaker panel to the crawl space.
 
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Old 04-26-10, 12:34 PM
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Originally Posted by ray2047 View Post
The wire probably doesn't have enough slack to splice in the middle so you will need to use two Jboxes about a foot apart with a short length of new #12 cable between them. You can come off either box for the refer receptacle.
I'd suggest that a better solution would be to add a new J-box where you'd like it and then run new wire from that box to the existing receptacle. It takes a bit of new wire, but I'd personally avoid having two new j-boxes just for some splicing slack. Two boxes would just bother me.
 
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Old 04-26-10, 01:26 PM
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Lots of good advice here!

Please explain why the transformer for the low voltage system shouldn't be plugged into the outlet with the microwave oven. (It is basically a plug-in, not hard-wired microwave oven installed in a cabinet with trim.) I understand that by definition this could be considered a small appliance circuit. How is it against code to use this outlet to supply a plug-in, low voltage transformer?
 
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Old 04-26-10, 01:34 PM
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The reason for the two j-boxes makes sense to me. It is probably true that I don't have enough slack. Nevertheless, I would have the microwave oven oven on the same circuit as the spare refrigerator, which furd points out may be too much load at times.

But I would still like to understand how to do this with one j-box. There would always be the problem of too little slack no matter which cable is spliced into. I'm missing something here.
 
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