I have to change our sauna heater. The current heater has wires connected to Earth, N and L3.

I'm confused by the manual of the new heater as there is only 1 X N wire but the manual seems to suggest that there should be 2 (unless I've misread it).

The shop said that the wiring would be the same.

The new heater model is numbered 1 - 7 so it's the top diagram that seems relevant.

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  • There are quite some energies involved here, are you sure that -- if at least only for insurance reasons -- you want to do this yourself when unsure? – PlasmaHH Aug 16 '16 at 15:47

The diagram gives you three possible wiring options depending on your power system. The top one is for 415V three-phase (star), the middle for 240V three-phase (delta), and the bottom one for 240V single phase.

In a normal house the bottom one is what you want. Basically connect all the N terminals together, and all the L terminals together and those are your N and L points.

Note: the lower two diagrams are the same physical connectors as the top one - they just omitted drawing in the connection 7 that not used for the lower two diagrams.

  • It's the top diagram. I have one N wire from the existing heater but this diagram for the new heater seems to suggest that I need 2 connected to 2 + 3? – user598200 Aug 16 '16 at 15:45
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    No, it's the bottom one. They are all the same, just without using pin 7. – Majenko Aug 16 '16 at 15:46
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    The heater consists of 3 individual heating elements. You wire them differently for different types of power. Unless you are in an industrial environment (such as a leisure centre) you will be single phase 240V. Ergo you wire the three heating elements in parallel as shown in the section labelled 240V single phase. – Majenko Aug 16 '16 at 15:48
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    That gives you then one neutral, one live, and one ground. You then separately tie the two neutral connections together, and all three live connections together. Depending on how it is physically this may be done with a bus bar. – Majenko Aug 16 '16 at 15:50
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    Now that you have added a picture you can plainly see the bus bar (copper strip) joining L1, L2 and L3. – Majenko Aug 16 '16 at 15:58

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