H20 Heater and dishwasher tied together
Oak River Mike
| Posted in General Discussion on
Hey guys,
Electrical question for you all.
I got hold of an old dishwasher for my shop from a kitchen remodel I did. Going to use it for dog bowls and car parts. (Yeah I know “What?!” Thats what my wife said)
Anyway, I already have a small 10 gallon 110v water heater in my shop on a 20 amp home run back to the panel. Can I tie the dishwasher into that same line or do I have to run a new home run top the panel for it?
I don’t want to as getting the line run in conduit and all will be a challenge as my shop is so full! But I will if I have to so as not to burn the place down.
What do you all think?
Mike
Replies
That will likely suck too much juice for the breaker to hold, unless you disconnect the heating element in the DW.
Mark,
I was wondering about that as the heater is rated at 2000 watts.
Mike
I don't think the rest of the dishwasher uses a lot of current. You could just use air dry, unless the dishwasher also heats the water while washing, I think most do, but you may have an economy setting that will turn off the heater while washing.
Its an old dishwasher from the 90s so I am fairly certain it doesn't heat nor do anything more than just have the optional electricair drying. I could leave it on air dry as its nothing more than the dog dishes.
Count the watts. if they add up to 4,400 you may make it, but if stringing the line is straightforward that is what you should do.
"Count the watts. if they add up to 4,400 you may make it, but if stringing the line is straightforward that is what you should do."Where did you get 4400 watts from?That number does not make any sense..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
yeah i was gonna say that too, breakers are measured in amps not watts, watt does that have to do with it?
Well heating devices and other loads such as TV and computers are rated in watts. So you need to convert one to the other to determine the total loads.And specially in figuring total demand where you have both 120 and 240 loads.I was not questioning the fact that he used watts. Rather that number that he used. Makes no sense..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Sure it makes sense 4400 watts on a 120v circut comes out to about 36 amps, so I suppose we could see what wears out faster the breaker or his wrist from having to reset it ;-)
Bad math bad thinking, sorry, My small heater unit uses 220v wouldn't work anyway with 120 washer. As you all know the number should be 2400 watts max.
OK, so to review...the circuit is on a 20amp breaker (could easily increase it if necessary).
The 100v water heater label says it draws 2000 watts. The dishwasher says it draws a total of 10amps.
What say ye?
Edited 5/26/2008 6:06 pm ET by Oak River Mike
Lucie, 'splain to me how you can "easily" increase the size of the breaker.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
I can put a larger breaker in the space. (Maybe a 30amp) Its already wired with 10ga so I think its doable. If the calculations run it up to a point where a 20 amp would trip and a 30 amp wouldn't is what I am getting at.
2000 watts divide by 120v = about 16 amps add that to your 10 amp dw & get 26 amps max draw.
Fine for a 30 amp breaker, BUT 30 amp breaker equals 10 gauge wire.
12 gauge wire is limited to 20 amp breaker.
The breaker in the panel is to protect the wire not the equipment.
Thats exactly what I was talking about in my reply to DanH That 26 amp though is still kind of cutting it close so maybe I should just run a new home run to a new breaker? Its a 200amp panel with only about 10 spaces filled so thats not a problem...just getting the line to it! Thanks
Edited 5/26/2008 6:43 pm ET by Oak River Mike
You could install a disconnect to turn off the WH when the DW is running. (Don't use a regular wall switch, but something heavier.)
The WH draws 16.7 amps by itself.
Look on the lable on the DW. Min new one shows 2.2 amp motor, 5.5 heater, max 9 amps. But this is a new energy star DW.
IIRC my old one had drew about 4 amps for the pump.
If this is in conduit why not just pull another wire in the conduit. If you set it up as a multi-circuit all you need is one more hot.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill,
Good thinking but the conduit is already full with another run. I "might" be able to get one more hot in there but it would be tough.
Mike
Full by code or the conduit is jambed?
How far are the homeruns? You may have to derate the circuits if the conduit is too full.
Full by code and with the 3 or 4 turns it takes, jambed too!
Only about a 16-20' run so not sure if I have to derate....maybe?
Mike
I was hoping Bill Hartmann would have my back on this one. The only reason I know anything about this is because I had to run a conduit chase once and my cousin (Master sparky) really surprised me with how few wires you can run in a 2" pipe.
Derating is not done based on fill, but rather the equivalent number of current carrying conductors.That is one advantage of using a multiwire circuit. It still only counts as 2 current carrying conductors, but can get 2 120 v circuits out of it.But derating starts at anything longer than 2ft bundled or in conduit.I am not sure of the number, but if IIRC conduit is limited to 40% area fill..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks, as I said I only know enough about the subject to know that I have to be concerned about it.
We've got a sparky on staff now so I dont have to worry as much about these things.