electrical question, & I'll actually ASK it!
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electrical question, & I'll actually ASK it!
OK, this time, no endless wait for the question:
Why do they crimp the ground & neutral together on many 240V appliances?
If your power source has four wires (separate neutral & ground), isn't it better to make the four separate connections?
After all, most 240 V appliances (like ranges, wall ovens, cooktops) use 120 for the lights, clocks, etc... so the neutral has current running through it (or am I wrong?).
Thanks, I know just enough about electric to be dangerous!
Why do they crimp the ground & neutral together on many 240V appliances?
If your power source has four wires (separate neutral & ground), isn't it better to make the four separate connections?
After all, most 240 V appliances (like ranges, wall ovens, cooktops) use 120 for the lights, clocks, etc... so the neutral has current running through it (or am I wrong?).
Thanks, I know just enough about electric to be dangerous!
Hotshot
Joined: Jan 2002
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From: La La Land
Daddy,
I'd guess your understanding of electrical systems is pretty spot-on, from what you said.
There is no power running through the neutral or ground wires in most 220 volt systems. An example might be an electric kitchen cook top. Those usually have no white.
However, there may be times when current does flow. An example might be a 220 volt oven that also has a 110 volt clock in it. The amount of current to run the clock would run in the white wire, and one leg of the 220 would have the additional current to run the clock. It's kinda' uncommon, but it happens.
The green should be separate, connected to the metal chassis, and run all the way back to the Ground buss bar in the breaker box. If present, the neutral (white) should be run all the way back to the Neutral buss bar in the breaker box.
The only place the whites and greens should be tied is within the main breaker box when those buss bars are tied. Even sub-boxes should have separate green and whites running separately through them, and the two busses left untied.
So the answer to your question is: electrician is lazy, cheap, unschooled, or any combination of those.
Pop
I'd guess your understanding of electrical systems is pretty spot-on, from what you said.
There is no power running through the neutral or ground wires in most 220 volt systems. An example might be an electric kitchen cook top. Those usually have no white.
However, there may be times when current does flow. An example might be a 220 volt oven that also has a 110 volt clock in it. The amount of current to run the clock would run in the white wire, and one leg of the 220 would have the additional current to run the clock. It's kinda' uncommon, but it happens.
The green should be separate, connected to the metal chassis, and run all the way back to the Ground buss bar in the breaker box. If present, the neutral (white) should be run all the way back to the Neutral buss bar in the breaker box.
The only place the whites and greens should be tied is within the main breaker box when those buss bars are tied. Even sub-boxes should have separate green and whites running separately through them, and the two busses left untied.
So the answer to your question is: electrician is lazy, cheap, unschooled, or any combination of those.
Pop
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From: Lafayette, IN
+1 on what Pop said. He nailed it. If your 240V appliance does not need a neutral for 120V features, then the receptacle and male cord end should be changed to 3-prong. The white should then be capped off in the box behind the receptacle. If the 240V appliance DOES use 120V, then the neutral should absolutely NOT be tied to the ground wire for safety reasons--that ground wire is not to carry normal current.
Jason
Jason
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From: St Louis
240V kitchen and laundry appliances have two hot legs and a neutral that is grounded at the service panel.
If it is being installed in an older three-wire home, the case/cabinet is electrically tied to the neutral terminal effectively grounding it (assuming the connection in the panel is correct).
If the appliance is being installed into a newer 4-wire installation, the neutral and ground are separate at the appliance. The neutral and ground are still required to be connected at the service panel.
I peddle appliances and have never seen one that had the neutral and ground connected at the appliance except with an easy to remove jumper or strap, never have seen one crimped.
Steve
If it is being installed in an older three-wire home, the case/cabinet is electrically tied to the neutral terminal effectively grounding it (assuming the connection in the panel is correct).
If the appliance is being installed into a newer 4-wire installation, the neutral and ground are separate at the appliance. The neutral and ground are still required to be connected at the service panel.
I peddle appliances and have never seen one that had the neutral and ground connected at the appliance except with an easy to remove jumper or strap, never have seen one crimped.
Steve
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Well, I guess I did have it right then.
I have two wall ovens that I am fairly certain use 110 for the interior light and the digital keypad controls but on both the white & ground wires are crimped together by the factory, not the electrician...just trying to figure out why?
I have two wall ovens that I am fairly certain use 110 for the interior light and the digital keypad controls but on both the white & ground wires are crimped together by the factory, not the electrician...just trying to figure out why?
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Post Fiend
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From: Where's my map???
In a single phase, the ground and nuetral are one in the same. They are crimped to make sure the unit is infact grounded. Trace the green wire, and you will see it is grounded to the body of the unit.
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From: Lafayette, IN
Frank, from a pure electrical point of view, you are correct. However, electrical code is very clear on this that the ONLY place the two are to be bonded is at the main service panel. This is for safety reasons and to prevent the ground wire (bare or green jacket) from carrying the normal "return" current. There are a number of bad scenarios that can arise from current flowing in the ground wire in non-fault situations. Not to mention, the ground wire is often sized smaller than the current-carrying conductors, so if a break occurred in the neutral, the ground would carry the full current, and if that current were close to the rating of the hot wire, the ground could overheat.
Jason
Jason
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From: Where's my map???
Jason, I agree with what you are saying but, a house that was wired 5 or more years ago never had that extra ground wire. So when you disconnect your old stove, oven or whatever and replace it with a newer model. You are left with the same wiring, or if it's a plug in. you don't have the options as the new codes require. No?
Just asking, cause now I am confused.
Just asking, cause now I am confused.
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I'll agree Frank, & if it's a hot water heater, it makes no diffo anyway.
But my original question was, if the appliance uses any 120, even the small amount a light bulb draws, why wouldn't it be better to use the four separate wires if you have them? That's why I don't understand why the factory crimps those wires.
But my original question was, if the appliance uses any 120, even the small amount a light bulb draws, why wouldn't it be better to use the four separate wires if you have them? That's why I don't understand why the factory crimps those wires.
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From: Southeastern Indiana
Originally Posted by jroehl
Frank, from a pure electrical point of view, you are correct. However, electrical code is very clear on this that the ONLY place the two are to be bonded is at the main service panel. This is for safety reasons and to prevent the ground wire (bare or green jacket) from carrying the normal "return" current. There are a number of bad scenarios that can arise from current flowing in the ground wire in non-fault situations. Not to mention, the ground wire is often sized smaller than the current-carrying conductors, so if a break occurred in the neutral, the ground would carry the full current, and if that current were close to the rating of the hot wire, the ground could overheat.
Jason
Jason
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From: Lafayette, IN
Originally Posted by tewferford
Jason, I agree with what you are saying but, a house that was wired 5 or more years ago never had that extra ground wire. So when you disconnect your old stove, oven or whatever and replace it with a newer model. You are left with the same wiring, or if it's a plug in. you don't have the options as the new codes require. No?
Just asking, cause now I am confused.
Just asking, cause now I am confused.
Jason
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