Tapping the dryer circuit

Merry Christmas
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If i see a 30 amp 240 receptacle i assume it to be able to supply 30 amps with no limits and that 120 volt be able to provide 20 if its in a washer location.Will it work if sub panel is installed ? Well for last year i was forced into that situation while we remodeled.It did trip several times but we managed.I blame most of that on a piggyback breaker 20/30 30.The breaker tripping was never the 2 pole 30 feeding that sub panel.But that did not make it legal or right,it simply worked.Fixed now
 
sfav8r said:
....I got involved because one of the new owners bought a stack washer/dryer that requires 220 and 120. When he contacted the builder, he said "it's your problem.....
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Not if your new owner has a good lawyer. There have been cases like this around here, and the builders and the electricians will lose such cases, if the local jurisdiction has adopted the NEC.
 
hmspe said:
There's also no mechanism to assure that the L1 terminal in the dryer actually gets connected to L1 in the panel, especially when it's the delivery guy from Best Buy installing the whip.
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How about install a 4 slot sub, put in the 2 pole for the 240v, and then do an eany meany miny moe to choose which of the other 2 slots you'll use for the single pole. . Stick in the single pole, and before you start removing KOs from the cover, turn both units on.

If a breaker trips then move the single pole to the other slot and assume your eany meany miny moe was faulty.

David
 
David, I'd prefer using a clamp-on ammeter to determine which leg of the dryer is using less power.
 
dnem said:
Martin,

Those are legitimate questions and maybe answers will be posted but I think it's important to ask what is the likely worst case scenario if the dryer is replaced. . Isn't the likely worst case scenario that the breaker will trip ?

That doesn't seem that bad to me.

David
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I'd cite 215.2(A)(1):
General. Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts III, IV, and V of Article 220. The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.

Adding a panel to what was a 30A, 240V dryer branch circuit turns the conductors into a feeder. While it may be true that it would (or could) work in real life, it would not be Code compliant unless you could prove by calculation that the feeder ampacity meets 215.2(A)(1). Per 220.52(B) and 220.54 the load on the leg with the washer would be 33.3A.

The future owner aspect is also very significant in my mind. We have very strict laws here about "full disclosure" on any known defects when we sell a house. What happens when a future owner has a problem, calls in an electrician, and they find a clear Code violation that you didn't report? And what about fire danger? A 30A breaker takes a long time to trip on a small overload. If there's a fire and the insurance investigator traces it to a non-compliant installation who gets sued?

Most people here could probably play "eany meany miny moe" to get the washer on the low leg, but future owners would not know to do that and probably wouldn't be capable. I've never known of a homeowner who called in an electrician to plug in the dryer. The electrician would only be called if there was a breaker tripping problem. I see three possibilities: (1) You left behind a note on what you did and why. You've just left a smoking gun for the law suit because you've admitted violating Code. (2) The electrician recognizes the violating and fixes it properly. The new owner gets a big bill. Who does the new owner send the bill to? Does he file a complaint with the Registrar of Contractors over the issue? (3) The electrician recognizes what's been done and moves the breaker for the washer to the other leg. Now he's also violated Code, which opens him to liability.

Martin
 
(4) You find a 2-pole, double-throw switch and use it to assure both appliances cannot run simultaneously. You'd still need to protect the 120v receptacle @ 20a.
 
LarryFine said:
(4) You find a 2-pole, double-throw switch and use it to assure both appliances cannot run simultaneously. You'd still need to protect the 120v receptacle @ 20a.
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When you fiind a woman in the USA who's willing to not run the washer and the dryer simultaneously please let me know.
 
I just bought a new boat. I'll do the windows;)

My opinion. It's got to be fixed and fixed right. If you have to run pipe on the outside of the house, then do so. There's no quick fix here.
 
hmspe said:
I'd cite 215.2(A)(1):
General. Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts III, IV, and V of Article 220. The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.

Adding a panel to what was a 30A, 240V dryer branch circuit turns the conductors into a feeder. While it may be true that it would (or could) work in real life, it would not be Code compliant unless you could prove by calculation that the feeder ampacity meets 215.2(A)(1). Per 220.52(B) and 220.54 the load on the leg with the washer would be 33.3A.
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Go ahead and kill my eany meany miny moe buzz with all of your fancy high falootin' code talk
 
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