Hello, I have a pool heater that I would like to power with my single phase 220 service. The heater arrived as a 3 phase unit.
The incomplete instructions say to install as single phase.
My electrician asked me to get instructions but the seller is hopeless in that regard.
I have a 220, 30 amp circuit available nearby.
Here are photos of the situation.
If you can give me some instructions that my electrician can follow, I would be grateful.
I hope you can seethe attachments.

 

They are wired as 3 phase and neutral, IOW each element is separate on each phase to the star neutral, all you need to to is to wire each red from a black (blue) from a double breaker for each element. and install three 10 amp double breakers.
Which is one way to do it on a residential service panel.
If retaining the contactor, it will only switch one conductor for each element.
The total demand on 240v 1ph is 23amps
Or feed them from a single 30amp double breaker.
Max..

 

Thanks Max,
I will show your reply to my electrician.

 

If you run a single pair for 30amps you should wire in #10AWG.
Running to three separate elements you would need 3 pairs of #15AWG
Max.

 

MaxHeadRoom is right on, but thought I may add:

I would personally think the homeowner would not be thrilled with you using three 2-pole spots in his panel. I would surely look into Max's suggestion for a single 30A 2-pole breaker.

Past that, you can use a 3 phase contactor for single phase operation, you will simply need to distribute the load across the three contacts. (Max may have been suggesting this, I am unsure)

I drew of super quick picture of how I would approach (which is largely what has already been suggested). (image pending, site won't let me attach right now)

 

Here it is:

 

The only thing is the 'black & red leg' you show would have to be upped in size over its original star neutral connection to #10 for each.
Max.

 

Stuntman,
Thank you for taking the time to do the drawing.
and Max for the #10 advice.
The single breaker is better also because there is a seldom, but occasionally used clothes dryer on the circuit as well.
I really appreciate you making things clearer for me.

 

The only thing is the 'black & red leg' you show would have to be upped in size over its original star neutral connection to #10 for each.
Max.

Agreed,

The only place you could get by with smaller (<10AWG) wire would be the leads from T1, T2, and T3 to the element terminals. If it were me, I'd use 10AWG for everything and be done.

However, by saying 10AWG, we are assuming that the wire is run in such a way that NEC derating does not necessitate going to an even larger wire size (ie: the wires from the breaker are installed in conduit with too many other current carrying conductors). The electrician should be able to figure this based on the installation.

 

I have finally had my electrician over to look at this again. The 220 supply we have has 4 wires: red and black are the hot, and white is the neutral, and we have the bare ground. In my ignorance I may have led you to believe there was a single hot wire.

So is there a way to wire the 2 hots to the three reds at the heater?

If this is not possible can we wire the 2 hots to just two of the heater's reds and just use 2 elements?

thanks.

Our supply circuit wiring is #10

 

You do not need the neutral, wire as post #6 shows for the 3 elements, if you just want one or two elements, wire accordingly and leave the other disconnected, .
Wire all in parallel if you want to by pass the contactor but you need to switch it somehow, IOW wire the 3 reds in parallel like the black..
Didn't your electrician see it?
Max.

 

Max,
Is this what you are recommending?
Thanks for your patience.
Donn

 

Yes, basically what @Stuntman posted.
Max.

 

Th-th-thanks M-M-m-max

 

Th-th-thanks M-M-m-max[/QUOTE
I/m not an electrician however since this is a pool area doesn't one need ground fault protection?

 

I/m not an electrician however since this is a pool area doesn't one need ground fault protection?

Yes.
Max.

 

Howdy, I have exactly the same heater. I understand both diagrams. I have a 50amp dedicated ground fault circuit for this heater. How will the ground fault breaker react to the second diagram showing the 4 wires, ground, neutral, and 2 hot wires red and black?

@MaxHeadRoom

 

How do you mean, "how will it react"?
It should trip on a GND fault.

 

I'd be concerned about what the white wire is... The original 3 phase had the black on "neutral". The new red/black are both "live" and that is a bit different. So, what is the white wire for? What are the voltages across those 3 wires? Why is there a neutral on a 220V system?

 

The original system was a 3ph and star neutral system, IOW each bank was fed from a 220v phase and a neutral.
The new system just feeds all from the 240v 1phase.
I gather it must have worked after four years on!