Outlet for Microwave hood

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  #1  
Old 03-24-05, 06:04 AM
briante
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Outlet for Microwave hood

I hope I am using the correct forum, my appologizes if I am not.

I have ordered a microwave oven/ range hood combo to replace my current range hood. While I am waiting for it to be shipped I have started to look into putting a plug in the above cabinet for the microwave. The current hood is hardwired. I took a look at the wires that were supplying power to the hood and found out that they are only 2 conductor (black/white). The house is about 40 years old.

My question is: When I pull the existing wires into the new outlet box for the plug, should I run a ground wire for the new microwave? If I should, can I run it down through the wall and ground it on some copper pipes that are connected to the neighboring bathroom or do I have to run it to the panel? Is there another way?

Are there any other things I should worry about?

Thanks for your advice in advance,
Brian
 
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  #2  
Old 03-24-05, 06:50 AM
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You MUST have a properly grounded circuit for this microwave hood.

The safest way to ground this circuit is all the way back at the main panel. Do not ever connect a ground wire for a circuit to a copper pipe. This is dangerous and creates a hazard.

Rather than messing with the existing circuit, I would run a new 20 amp circuit all the way back to the panel.
 
  #3  
Old 03-24-05, 08:47 AM
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I would like to reiterate what Bob said about not using a nearby copper pipe for a grounding connection. Doing so would be much worse than no grounding connection at all.

Although Bob's suggestion of a new circuit for your microwave is clearly the best plan, you might be able to use the exisiting circuit if there is nothing else on it at all. To make sure, turn it off and test everything in the area to see if it still works. If there is anything else that doesn't work with this breaker off, then you should run a new circuit.

If this is indeed a circuit with nothing else on it, you can install a GFCI receptacle on an ungrounded circuit for your microwave. Make sure the receptacle is somewhere where you can reset it if necessary.
 
  #4  
Old 03-24-05, 08:57 AM
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Let me clarify my post, as John and I disagree on one point.

I stated that you must have a properly grounded circuit. I even put MUST in upper case to make it stand out.

Microwave ovens contain electronics. Most electronics want a good ground. I have no doubt that your microwave would work using a GFCI on an ungrounded circuit, and yes this would be safe. However, I maintain that using an ungrounded circuit will not sit well with the electronic controls of the microwave, and they will not be happy and it may shorten their life. Further, I believe that the manufacturer of the microwave hood states that their product MUST be installed on a properly grounded circuit.

For this reason, I would install a properly grounded circuit, or at the very least properly ground this circuit.
 
  #5  
Old 03-24-05, 09:49 AM
briante
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Bob & John,

Thanks for the replies.

I will ground my circuit to the panel. I have tested the current circuit, and the only other items on it are some basement lights (about 8, 60w bulbs). I have noticed that they ran a new circuit for the gas range and it is properly grounded. Would I be able to gound this circuit by tapping into the range's gound(instead of running it all the way back to the panel)? It is not that I am against running a new circuit, I am just trying to do it the easiest, least time consuming way. Is there another way to properly ground the existing circuit?

Let me know if tapping into the ground from the range is a bad thing, then I will run a new circuit.

Thanks again,
Brian
 
  #6  
Old 03-24-05, 10:48 AM
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Is this a gas range with a regular 120 volt circuit? If so, a better solution would be to extend that circuit for the range hood.

Is this an electric range? Don't tap an electric range circuit for a ground. If it's a three wire circuit then you don't have true ground. If it's a four wire circuit then you have a wire size difference.

Be careful trying to use this existing circuit. 8 times 60 watts is 480 watts. If this is a 15 circuit then you only have 1320 watts left over for the microwave. if this is a 20 amp circuit then you have 1920 watts left over for the microwave. You may not have enough power to turn the basement lights on when using the microwave.
 
  #7  
Old 03-24-05, 11:32 AM
briante
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Originally Posted by racraft
Is this a gas range with a regular 120 volt circuit? If so, a better solution would be to extend that circuit for the range hood.
The range is GAS with a standard 120v circuit. I'll double check to make sure the range is the only thing on the circuit breaker. If it is, you're saying I can use this circuit to power our Microwave and range at the same time, right? That sounds like a winning plan.

Thanks for your help,
Brian
 
  #8  
Old 03-24-05, 01:07 PM
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This makes more sense than using the basement light circuit and stealing a ground from the gas range circuit.
 
  #9  
Old 03-29-05, 05:41 AM
briante
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The range is not on its own circuit. So, I have decided to run a new circuit from the panel. I am going to use a 20 amp breaker, with 12g copper wire. I am connecting it to a single 20 amp outlet, not a duplex.

My question is, should I use a GFI circuit breaker, or can I get away with a standard circuit breaker?

I have everything purchased, except for the breaker.

Thanks again,
Brian
 
  #10  
Old 03-29-05, 07:18 AM
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A standard breaker is just fine, unless your microwave manufacturer requires GFCI in the installation instructions. I would think that's a rare situation.
 
  #11  
Old 03-29-05, 07:36 AM
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No need for GFCI.
 
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