Hoping to get some help understanding this sauna heater wiring diagram. Pics at bottom.

Disclaimer that I have an electrician friend "helping" (not for free though!) me on the weekends so I can't go too far wrong, but I am doing the runs and prep work to help the project go faster -- and also just have an inquisitive mind toward learning and understanding all of this. That is just to say, don't be afraid to answer for educational purposes.

The unit consists of a wall-mounted controller (outside of sauna) and the heater itself + temperature sensor, inside the sauna.

The controller is supplied with 240v and contains the relay and PCB/controls to turn on the unit. Upon turning on the unit, obviously the heater is energized.

It's a 9KW heater. I have 6/3 with ground on a 50 amp breaker running to the sauna location.

It also has an option to power a 120v light (inside the sauna) from the controller, which I will not be taking advantage of.

My questions:

  1. Will I be using the neutral from the 220 run at all? (remember I am not going to use the 120v light option)

  2. I am generally confused about the jumpers on NN / LL for the power input, but only on NN for the output to the heater.

Generally, looking for confirmation on what goes where :) Would appreciate if you could help demystify for me!


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Here are all 3 wiring diagrams supplied in the manual. I assumed the top one was relevant for me but perhaps not.

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  • Is this the only wiring diagram? It looks like this diagram is for one hot leg and a neutral since the two "L" 's are jumpered. there should be another diagram for using two high legs and instructions for removing the jumpers. It appears you'd need the neutral for the heater relay and the pcb board which appears to have a tx that powers the board.
    – JACK
    Oct 31, 2019 at 13:54
  • 1
    @JACK Just updated the OP with a new picture at the bottom, showing all 3 from the manual. It seems like the other options have fundamentally different pin outs and such (i.e., ground in different spot) so I had disregarded them. Wrong?
    – Dave
    Oct 31, 2019 at 14:09
  • Is your supply American style split phase 240 or Euro style 220-240? Oct 31, 2019 at 14:32
  • 2
    Hey guys - thank you. Glad to know I wasn't going crazy - yes, my supply is US style and it seems they just provided the wrong controller. Thanks.
    – Dave
    Oct 31, 2019 at 15:31

3 Answers 3


The bottom drawing is for European 3-phase "wye" power with 3 legs of 240V and a neutral in the middle. All connections are made hot-neutral.

The top drawing is for European single-phase (aka 3-phase "wye" where your house is only provisioned with one of the phases). It has one leg of 240V and neutral.

The middle drawing is made for North America/Japan/Philippines "240V with neutral in the middle" (note the 60Hz assumption which is correct everywhere but southern Japan). Both hots have to be switched, so they change out to a much stronger single relay that switches both legs.

Not shown: the drawing to wire this up 208V/240V "delta", which you might do in New York City, Brazil or anywhere with wild-leg delta service. That wires up just like #3 except the 6 heater terminals are rearranged G U V U W W to put the 3 heating elements in a triangle (delta).

The reason for so many terminals is so they have the maximum flexibility to support a wide variety of configurations. In fact there is nowhere in the world you can't wire this. You only need to hook up 2 wires (other than ground) and also assure the relay is 2-pole and the heater jumpering is correct.

Do not continue if you see a 3-pole relay, you may think "extra pole, who cares" but the 2-pole relay handles larger amperage!

Keep in mind yellow/green is always ground (as is green or bare) worldwide.

  • 2
    I ended up seeing a 3-pole relay. Reached out to the manufacturer about getting the right controller.
    – Dave
    Oct 31, 2019 at 16:35

First where are you! I am guessing North America from your description of your power (it sounds like split phase 240v) To me it looks like you need the middle one with the L1 &L2 feed That would be split phase like used in the U.S. the top one is other side of the pond where 220-240v to neutral is the type of power The last 380-415 you know you don’t need since you said 220v. The jumpers at L1& L2 provide multiple outputs from the feed. The L3 & L4 jumpers do not appear to do anything but may be connecting things not on the print. So again you need the middle print since you said 220/240v and you have a separate neutral. L1 is one hot and L2 is the other hot. Hope that helps.

  • 2
    If this is correct, (and I believe it is) then he's going to need to get a new Controller from the manufacturer. The one he has is for euro style Oct 31, 2019 at 14:40
  • 2
    I just looked and think you are correct Chris, I did not look at the controller itself and figured it was universal, but looking at them I believe the OP will need a different controller.+
    – Ed Beal
    Oct 31, 2019 at 14:50

The second diagram is the one you want based on the service you have to the sauna. You will not need the neutral if you don't want the light but you should install it anyway just in case. The jumpers, as Ed described in his answer, just provide for additional connection points, this same panel is probably used for different size heaters.

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