Grounding clothes dryers

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BLA

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A dryer circuit cable is 8/2 with ground USE (outerjacket is rated for the voltage) and a new automatic service rated generator transfer switch is installed within 5' of the Loadcenter. The electrician installs a grounding bar in the existing loadcenter. He or she moves the grounding conductors from the isolated neutral bar (isolated now) to the new bonded grounding bar. Now the USE ground conductor remains on the isolated neutral bar. I served a 5 year apprenticeship. I have 30 years in the electrical field and 6 years as a certified electrical inspector in my state. I don't know everything there is to know. Can someone explain, in solid electrical theory terms, what the danger is in leaving the dryer circuit alone.

Thanks in advance for all responses.
 
If anything leave the dryer wire (3rd wire attached to the neutral buss, because it is a current carrying conductor not just a ground!) As you being an inspector though you should choose whether or not to allow the dryer wire to remain. At mininmum I would at least wrap with white tape or use heat shrink to identify that it is indeed a grounded conductor not a grounding conductor(EGC).

A dryer uses one leg and the grounded(neutral) conductor for 120v to run the motor and both legs (240v) to run the heating elements.

Just for clarification I believe you ment to say SEU cable not USE, correct?

This is touchy when an existing dryer or range which was OK to feed with 3 wire comes after a situation in which a panel now becomes a sub panel with a 4 wire setup.
 
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BLA said:
Are you saying that bonding the dryer to the grounded wire was a danger?
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There is more risk and ever since the 1996 NEC you were not permitted to make new installations that bonded the frames of ranges and dryers to the neutral conductor, You were only allowed to leave existing installations that were like that as is for the most part.

Problem is you changed the point where this is supplied from to a feeder supplied panel instead of a service supplied panel, now all EGC's need to be separated from the current carrying neutral conductors, as has been mentioned. I also agree that if you are going to leave the cable that it is better to leave it connected to the neutral then the EGC because it does carry current - but is still in violation of NEC.
 
I had one inspector that, in this type of scenario, would make us lift the ground from the ground bar and tape it with white tape and put on the neutral bar.
 
If possible change it out to a 4 wire cable and be safe about it. You may have the same issue with the range cable
 
BLA said:
Are you saying that bonding the dryer to the grounded wire was a danger?
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No, that is not what I am saying. I am saying you have a minor code violation but no added danger compared to the original set up.

There is good reason that we are no longer allowed to use the grounded conductor to bond frames of dryers anymore, and why the a three wire dryer circuit had to go all the way to the service. In this case your really not adding neutral current to equipment grounded objects in the house and the shock hazard from a lost dryer neutral is the same.
 
Grounding clothes dryers

Excellent discussion folks. I really appreciate airing this one out.

I completely agree with all new construction having a 4 wire dryer and household electric range cable. I would always attach the grounded conductor of these 3 wire cables to the now isolated neutral bar as well as insulate the bare conductor exposed inside the loadcenter. Also, the EGC must be taken out of the loadcenter and moved to the new service equipment and the grounding electrode system be inspected and improved as necessary.

Some AHJs dogmatically require the 3 wire dryer and range cables to be changed to 4 wire when a service rated ATS is installed. This raises the cost of installation for people unnecessarily, in my opinion, especially when proper grounding and bonding practices can be achieved.

P.S. - And yes I did intend to say USE cable in a previous post because there are some 3 wire cables manufactured in the past with this designation. Typically SEU is most common now because it has a flame-retardant covering. It was improved to reduce smoke in a building fire senario. Thank you.
 
BLA said:
P.S. - And yes I did intend to say USE cable in a previous post because there are some 3 wire cables manufactured in the past with this designation. Typically SEU is most common now because it has a flame-retardant covering. It was improved to reduce smoke in a building fire senario. Thank you.
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Unless dual rated as RHW or such USE cannot be used inside.
 
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