ECN Forum Forums General Topics of the Trade General Discussion Area Existing range and Dryer 3-wire circuits

Can someone give me code references or insight regarding service changes and how they affect existing range and dryer circuits. I'm upgrading an old 3 wire service to a 200 amp (disconnect feeding a main lug panel) 4-wire and am wondering if I need to install new 4 wire range and dryer circuits. This is an old flat top cinder block bungalow and needless to say, major destruction work would be required.

I will venture to say that you shouldn't have to upgrade the 3-wire range and dryer circuits. But, the ultimate decision belongs to the AHJ.

[This message has been edited by Mike (edited 06-28-2001).]

This may be up to your AHJ, but as I stated on another board, I think you should replace the cables & outlets or purchase service entrance equipment that has room for a couple of more 2 pole breakers & extend the 3 wire cables into the new service entrance box.

Although three wire feeds were allowed for these types of loads, they were not allowed to be fed from a sub-panel, which is what you will be doing when you upgrade the service.

The current requirement is 250-140(3). The old reference was 250-60(c).

Tom

[This message has been edited by Tom (edited 06-28-2001).]

I will always try to include a 3 to 4 wire upgrade in such a service change, however if we would like to delve into the NEC:

250-140's key word is 'existing'

250-142(b) EX #1 states;
The frames of ranges, wall mounted oven, counter-mounted cooking units, and clothes dryers under the conditions permitted for existing installations by Section 250-140 shall be permitted to be grounded by a grounded conductor

Ok, so tape that puppy up & off to the N-bar!

BUT WAIT !

90-5(b) Permissive Rules
nice if you do it, but don't gotta!

Ok, so on to the G-bar???

BUT WAIT!

Art 100, Special Permission;
basically what Tom said

So can we do a poll of AHJ's here?
Door #1--Noodle Bar
Door #2--G-bar
Door #3--rejected until a 4-wire set-up



[This message has been edited by sparky (edited 06-28-2001).]

I would use the neutral bus, because a dryer and a range use the grounded conducter for several 120 volt circuits within the unit. For the timers and lighting. I would never intentionally put current onto a ground detail.

If the connection is in the main panel were neutral and ground are bonded, I don't see a difference between doors 1 and 2. Since it is carrying current, I would treat it as a neutral. Door 3 is the safe way.

I am with silverbk, the neutral/ground MUST go to the neutral buss.
RickG