3 phase hot water heater

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augie47

augie47

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If it's 3 phase it would be 6000 / (208x1.732) or 16.5 amps assuming the heaters are wired equally to each phase with a 25 amp OCP device.
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augie47

augie47

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As seen above (ignoring my stupid) it will depend on how they are switched.
If all 18 kw can be operating at once, assuming equally dived load, 18000/ (208X1.732) = 50 amp actual load.
If it's a storage water heater, 422.13 would require it to be considered a continuous load thus 62.5 amps.
 
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K8MHZ

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Dennis Alwon said:
The 3 phase water heaters I have installed have single phase elements distributed over the 3 phases.
Click to expand...

Me too, but three phase elements are out there. I used elements similar to the one below in a paint stripper solvent bath.

31DdAXU96VL._SL500_SS500_.jpg
 
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GoldDigger

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K8MHZ said:
Me too, but three phase elements are out there. I used elements similar to the one below in a paint stripper solvent bath.
Click to expand...
Seeing the six terminals on it, I would have no problem calling it three single phase elements in one assembly instead.
Or is that just intended to allow either wye or delta connection? :)
 
Besoeker

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GoldDigger said:
Seeing the six terminals on it, I would have no problem calling it three single phase elements in one assembly instead.
Or is that just intended to allow either wye or delta connection? :)
Click to expand...
The OP states that there are six elements. If so, you'd have twelve terminals.
 
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GoldDigger

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Besoeker said:
The OP states that there are six elements. If so, you'd have twelve terminals.
Click to expand...

Maybe each of the six heaters the OP refers to has 6 terminals, making 36 altogether.
Or maybe they really are six single phase elements to be balanced over three phases. The OCPD setting for a three phase source will end up just the same either way the heating elements are built or connected. As long as you keep your 3.5 straight and use the right voltage number. :)
 
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iwire

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K8MHZ said:
Only if they all come on at the same time. Convention dictates that the elements are separated, top and bottom, and they don't come on at the same time.

So, if wired as usual, in two stages, that would be 9,000W for the total.
Click to expand...

Being as it is three phase it strikes me as commercial and the commercial ones I have wired would run all elements at the same time if the water temp was low enough. As the temp comes up the number of elements on line drops.
 
kwired

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K8MHZ said:
Me too, but three phase elements are out there. I used elements similar to the one below in a paint stripper solvent bath.

31DdAXU96VL._SL500_SS500_.jpg
Click to expand...

That element depending on actual rating has potential to be connected to single phase supply, three phase supply or even to a higher voltage three phase supply and connected in a wye fashion.

Say each individual element were designed for 277 volts you could connect all three phases of 480/277 to one end of each element and jump the other ends together to connect them in wye. Or you could connect them to 240 volts single or three phase at a reduced output from what you would have at 480/277, or even less output at 208 volts.
 
mivey

mivey

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kwired said:
That element depending on actual rating has potential to be connected to
single phase supply,
three phase supply
or even to a higher voltage three phase supply
connected in a wye fashion.

you could connect...them in wye
Or you could connect them...at a reduced output
or even less output
Click to expand...
The Bubba Gump connection collection. :D
 
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