working with Electricians heated floors. need to decide 120 or 240 volts. they are usually 120 in a single bathroom.

Electricians either need to use an existing circuit or bring in a new circuit.  Modern electrical code often requires bringing in a new circuit.  And your existing electrical panel often determines if you have extra capacity or not.  In the panel on the right you can see that there are plenty of knockouts available.  Either way this is a consideration for adding electric floor heat.  The age of th

I keep some metal boxes, mud rings, and conduit on the box truck.  I am not able to run a new circuit for you (you need to either be the homeowner or a licensed electrician).  But I am able to make it very convenient for you or the electrician.  

My conduit cutting saw that goes on the box truck.

metal box without mud ring.  With conduit attached.  One for heat cables and one for temperature sensing probes (I always put an extra for cheap insurance).  

box with mud ring before conduit connected.  

You can see that I add nail plates to protect the wire at the bottom.  The end of the conduit has plastic caps to protest the wires.  I install the wires in the floor.  Heat wires and temperature sensing probes.   The electricians make the connections to the thermostat.  

So then I level the floor and install rpm matts.  Then I mark the location of the things that heat wires cant go under.  

The heat cables need to be ordered exactly the correct length.  So this is another reason that I make a cad drawing first.  This requires having your cabinets and fixtures already decided.  

This is what it looks like after the cables are poured in and the tiles are in.  Now the electrician needs to come and connect the thermostat.  

I provide the thermostat.  You decide if you want it programmable or wifi.  

I check the resistance before and during installation to make sure that the cables are not damaged.  

The cables are sized by square footage at 2 1/2" spacing.  So that's what I go off of.  Because you can't cut the heating part (the coated red part), sometimes I make up the difference between sizes by adjusting the spacing ever so slightly.  I like these cables instead of matts because you can get close enough that feet are warm on toilet without melting the wax ring.  Same with toe kick on cabin