4500W element 240V v 220V (easy question) - Home Brew Forums

 Home Brew Forums > 4500W element 240V v 220V (easy question)

09-04-2012, 02:39 AM   #1
ekjohns
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May 2009
IL
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I am making a eBIAB system with 1 PID and 1 4500W element. At 240V this should pull 18.75A. I will be moving soon and plan to use the dryer plug and Spa panel so i think there is a chance it could be 220V which means 20.5A. However I think I read somewhere that the resistance of the elements is static so a 4500W element on 220V will run slightly under 4000W (18.2A). Is this correct? I want to use 20A plugs to save on cost and 4500W should be more than enough power for my 5 gal batches.

09-04-2012, 07:41 AM   #2
cockybitz
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Dec 2009
Iowa
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you are correct. However, saying "220" is really a misnomer. I believe 220 service is minimum voltage for service to a residence, so you are likely to have ~240.

09-04-2012, 01:50 PM   #3
WroxBrew
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West Roxbury, MA
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The load is as you've stated 4500 watts:

4500w/240v=18.75 amps

The NEC considers a HWH a continuous load therefore the circuit must be sized at 125% of the nameplate value:

18.75 amps * 125% = 23.4 amps.

Per code, you really shouldn't go over 3500 watts on a 20 amp breaker and 12gauge wire. Just be aware that your pushing it with that 4500 watt heater.

09-04-2012, 02:04 PM   #4
ekjohns
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IL
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I was actually thinking last night I might go with a 3500W element anyway which will be 14.6A + 1.4A for my pump will give me 16A. Will that be okay with 20A receptacles and 12 gauge wire? If I do the 124% rule that puts me at 20A which should be right at the max since that is only a theoretical load correct?

09-04-2012, 02:38 PM   #5
WroxBrew
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West Roxbury, MA
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I'm not an electrician, but 16 amps is the rating for continous load, which I think is 3 hrs at full blast. A 3500 watt heater should boil 5 gallon batches just fine, and if the name plate on the pump says 1.4 amps at 240v, all should be fine. I doubt the pump starting current, even with the heater at full blast, would be enough to trip the breaker as its a short duration.

09-04-2012, 07:46 PM   #6
stamandster
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Jun 2011
springfield, ma
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Quote:
 Originally Posted by WroxBrew The load is as you've stated 4500 watts: 4500w/240v=18.75 amps The NEC considers a HWH a continuous load therefore the circuit must be sized at 125% of the nameplate value: 18.75 amps * 125% = 23.4 amps. Per code, you really shouldn't go over 3500 watts on a 20 amp breaker and 12gauge wire. Just be aware that your pushing it with that 4500 watt heater.
12ga solid core shouldn't have anything over 20amp on it. But stranded could possibly handle more. It's all about surface area

... well if you were planning on using 12ga stranded on a 30amp circuit to power a 4500w element.

09-04-2012, 09:04 PM   #7
grandequeso
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jacksonville, fl
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#12awg thhn wire either solid or stranded is rated for 30amps at 90deg C. But the nec says not to use #12 for more than 20a. part of the reason for this is that the terminals you connect the wires to are only rated for 60deg C. therefore you would have to derate the wire to the minimum terminal rating or 20a on 12awg wire.

09-04-2012, 09:16 PM   #8
WroxBrew
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West Roxbury, MA
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My bad , Its a typo. I meant 10 gauge wire.

09-04-2012, 09:48 PM   #9
grandequeso
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jacksonville, fl
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#10awg at 90° C. is 35A. if you open a water heater you'll often see #12 awg solid wire. that wire has a different type of insulation than what is commonly available. I believe it is rated for 105°C. either way they full under th UL regs rather than the nec.

09-04-2012, 11:19 PM   #10
Malticulous

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St. George Utah
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My roofing welder (for single ply) has a voltage gauge. Often reads 250 and can drop below 220 when heated up. The voltage drop comes from the resistance in the wires all the way from the service transformer. That thing does not even pull 20 amps but I use 50 foot of 8 AWG and 150 foot of 10 AWG from the job site temporary service. You will get more power out of your element if you over size your wire.