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Old 03-29-2008, 10:19 PM   #1
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help with disposal circuit


Hi there,

This is my first post and I need some help. I have added 4 halogen can lights to the kitchen soffit and since the sink light used the same circuit as the garbage disposal I just tapped into that circuit for the soffit lights. My GE 1/2hp disposer has 4.5amp (I calculated 540 watts) at 120V on the label. No idea of wattage for startup, so my lights are pulling 60x5=300watts plus the disposer. Am I at risk of loading the circuit? It has not popped the breaker ever but does dim the lights slightly when I activate the disposer. Now I need to add 3 pendant lights at 60watts each over the stove. Can I use the disposer circuit or should I just run a new breaker to the lights? The circuit is a 15amp line to the disposer. I believe the line can handle 1800 watts but am I pushing it now or by adding 3 more lights?

I'd appreciate your input.

Cheers,
Matt
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Old 03-29-2008, 10:44 PM   #2
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help with disposal circuit


If it's not too much trouble, I'd run a seperate circuit for the disposal. Keep all the lights together. This should mitigate the dimming problem as well.
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Old 03-30-2008, 07:55 AM   #3
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If it's not too much trouble, I'd run a seperate circuit for the disposal. Keep all the lights together. This should mitigate the dimming problem as well.
That's the issue. It is somewhat of a PITA to add the circuit because the wires are run through hard conduit and it on an outside wall. Safety first, which is why I ask, but if dimming lights will be the only problem, I could live with that. Do I risk a fire with lights on, each time I use the disposer though?
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Old 03-30-2008, 08:13 AM   #4
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That's the issue. It is somewhat of a PITA to add the circuit because the wires are run through hard conduit and it on an outside wall. Safety first, which is why I ask, but if dimming lights will be the only problem, I could live with that. Do I risk a fire with lights on, each time I use the disposer though?
It would be best to put the disposal on its own. That said, you are only at 8.5 amps with disposal running and all lights burning including the 3 new pendants.

Jeff
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Old 03-30-2008, 08:22 AM   #5
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It would be best to put the disposal on its own. That said, you are only at 8.5 amps with disposal running and all lights burning including the 3 new pendants.

Jeff
Thanks Jeff.

It's the startup amps that concerns me. I understand the startup wattage on the disposer can be as high as 1500watts. Whats the danger there?
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Old 03-30-2008, 08:29 AM   #6
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Thanks Jeff.

It's the startup amps that concerns me. I understand the startup wattage on the disposer can be as high as 1500watts. Whats the danger there?
None.....other than the lights will dim. Your breaker is designed to handle the short term start-up load that anything with a motor will cause.

Jeff
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Old 03-30-2008, 08:30 AM   #7
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Thanks Jeff.

It's the startup amps that concerns me. I understand the startup wattage on the disposer can be as high as 1500watts. Whats the danger there?
None. Your refrigerator, air conditioner, washer, dryer and anything else with a motor does the same thing.
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Old 03-30-2008, 09:56 AM   #8
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help with disposal circuit


There is no risk of fire with what you are doing. The circuit breaker will trip if you overload the circuit. The high starting current to the motor (called inrush) is causing a dip in the voltage which causes the lights to blink. That is normal and is no problem if you don't mind it. Even with the 3 lights you wish to add, the circuit will be far from overloaded. It is very common to put the disposal on the same 20 amp circuit as a dishwasher. Your disposal and 7 lights on a 15 amp circuit is not a problem. 1020 watts on a 1800 watt circuit.
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Old 03-30-2008, 12:48 PM   #9
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Just for info, the start surge of most motors is around 6 to 10 times the running current.

Most breakers can handle a surge of around 10 times the rating.

These figures are approximate.

If you can live with the lights dimming, you'll be fine with your project. No code issues, no hazards, it'll be safe.

Rob
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Old 03-30-2008, 02:23 PM   #10
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If you ae concerned about wattage start using halogen lights.
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Old 03-30-2008, 03:33 PM   #11
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If you ae concerned about wattage start using halogen lights.
The soffit lights are 60W halogen but not low-volt. The pendant lights will be incandescent though. Why are Halogen lights better for this?
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Old 03-30-2008, 05:09 PM   #12
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I apologize, I jumped too fast. I just installed 3 three spotlight type lights under a stove hood. They are low wattage but they use LED's not halogen bulbs.
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Old 03-30-2008, 09:11 PM   #13
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I'm not sure I understand how having the raceway in conduit is a hinderance. Is the pipe full? Is it too hard to get to?
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Old 03-31-2008, 07:26 AM   #14
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I'm not sure I understand how having the raceway in conduit is a hinderance. Is the pipe full? Is it too hard to get to?
Hi Goose134,

I can't seem to locate which way the pipes were run. They seem to go up instead of down into the basement and feed through other boxes along the way. So long as there is no danger, I'll use the disposer circuit for now and see how it works.
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Old 03-31-2008, 08:38 PM   #15
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Fair enough.
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