Hey Gang

I hope this is the right section for this. I recently installed porcelain tile over my levelled, basement slab with a Ditra Heat system. The mat and cable installation went smoothly and it's time to wire it up.

I'm pretty comfortable working with electrical in general but I've never wired up a floor warming system so thought it might be a good idea to come by here and see if anyone notices any holes in the plan, or if there are any possible pitfalls I should be aware of.

Wiring the sensor and heating cables to the thermostat is a no-brainer.

It's a 220v system. The specs on the heating cable are:

Ditra Model: DHEHK240225
Voltage: 240/208
Amps: 11.9/10
Resistance: 20.8 ohms

Cables were tested before, during and after installation with less than a 2% variance in ohm readings.

Now to the the breaker panel.....

Despite being a 220v system it's 15 amp, two pole (which is a bit new to me) but those are the specs. The plan is to run 14-2 BX to the panel and wire it into a Siemens 15A 2-Pole 120/240V Type Q Breaker Model # Q215. Common ground at the panel and both wires as hot for 220/240V

Does that all sound about right?

One other question.... I have a bunch of 12-2 BX left over. I assume it won't be a problem to use it instead of buying more 14-2... But is anyone aware of any code where it's prohibited to use over-sized wire? I can't imagine why but I can't find anything in our Ontario electrical code that refers to this.

 

Generic BX would not be appropriate but there are many variations.

Originally BX was steel with two copper wires and no ground.
Then a metal band was added for ground.
Then aluminum type cable called MC (metal clad) was introduced. It has a white, black and green copper wires in it. MC cable would be a correct choice.

Our current code requires that heating cable to be on a GFI circuit.
That means most likely you'll need a 2P15A GFI breaker in Canada.

 

Thanks. The BX I have available to me here is two (or three) copper shielded wire plus one unshielded ground wire. This is wrapped in a bare interlocked aluminum armour. I didn't even realize it is available without the copper ground wire.





The model of the two pole breaker I indicated is this one

 

That's called MC or metal clad. The original BX had a steel jacket and a much smaller ground wire.

That cable should be fine for your application. However that's not a GFI type breaker.
2P15A GFI circuit breaker

 

Yikes! I didn't catch that the first time you mentioned. I didn't realize this application requires ground fault.

Thanks!

 

PJmax - Wow! I guess I won't be buying it at Home Depot

https://www.homedepot.ca/product/sie...ker/1000406276

Ouch!

 

You can check with your local code to see if it's required. It is here in the States.

 

I'm just reading the specs on the Schluter site. They say they have built in GFCI but I imagine code trumps this if it says it's required

https://www.schluter.com/schluter-us...0the%20breaker.

 

It says the same thing on the Canadian site so it looks like an additional GFI breaker will not be needed.

 

Do you think there's any point to using one anyways? Would it provide an extra layer of protection or is it totally redundant?

I know.... Just that I'm the sort of person who has two smoke detectors in every required position instead of just the one.... For me, safety is worth a few extra bucks.

I've never had flooding but my (never used) basement sump pump has a backup pump that's powered by city water pressure should power fail