I very much doubt it. It would have been designed to operate on 3 phase power for good reasons, one of which being the amount of power it consumes. Single phase power will not supply sufficient power.

Also some three phase devices are 440 volt where as you can only get 220-230 volts from single phase. 

Looking at that manual supplied it says that the elements are all 400V requiring 3 phase and neutral.

There is no easy way to run this on single phase.

John

SATTV:

 

Looking at that manual supplied it says that the elements are all 400V requiring 3 phase and neutral.

 

There is no easy way to run this on single phase.

 

John

 

 

 

I think the SCA 60NB can be wired 3 or single phase. It appears to me the NB models can be either single or 3 phase but the NS models are only 3 phase.

To use single phase on the NB models you connect to the two right hand terminals (N, K) and the far left terminal (earth). Well that's how I read it. Happy to be proved wrong.

I think you only get rated output with 3 phase. In the case of the 60NB that rated output is 6 Kw (3 X 2Kw). With single phase you'll get a portion of the rated output.

SATTV:

 

Looking at that manual supplied it says that the elements are all 400V requiring 3 phase and neutral.

 

There is no easy way to run this on single phase.

 

John

 

Don't forget that the 3-phase system only has 415 volts across phases. From any 1 phase to neutral is 230V.

This heater has the elements wired in 'star' so yes, if certain conditions were met, it could in theory run on single phase.

The main technical problem is finding out what the maximum load of the device is. It may be too high to run from a single phase.

The main legal problem is that you need an SDOC (think of it as type approval) before your electrician will connect it. If he connects it without this, his head is on the block.

The way I read that diagram only H3 is powered with a single phase connection.

In the three phase connection each element is across one phase and earth, so each element is only being supplied with 230 volts.

While the elements might be capable of handling 400 volts as listed in the specs I don't think 400 volts is being supplied in this installation.

Technofreak:

 

The way I read that diagram only H3 is powered with a single phase connection.

 

In the three phase connection each element is across one phase and earth, so each element is only being supplied with 230 volts.

 

While the elements might be capable of handling 400 volts as listed in the specs I don't think 400 volts is being supplied in this installation.

 

If L1, 2 and 3 are connected to the same phase the unit works the same as if L 1,2 and 3 were to be connected to Phases 1,2 and 3.

Correct, each element is not exposed to 415V but rather to 230V.

You have to be careful with your terms because if you connect it to 3 phase, 415 V actually will 'be supplied'. However the device doesn't actually require 3 phases as it is not a synchronous machine nor are the elements connected in delta.

If it's the same as this one then it delivers up to 9kW. Back of the fag packet calculation shows single phase load of this would be 39 Amps but you'll need to de-rate your cable and other devices so you'll be building for 45-50 Amps.

Since most homes have a 63 Amp main breaker that doesn't leave much spare capacity for charging your phone (or cooking tea) while the sauna is on.

The main factor is it wired in star to or delta.

Star is where the heating elements are wired to between each phase and each other (with an optional neutral at the center), and each element sees roughly 230V RMS.

Delta is where they are wired phase to phase and see roughly 400V RMS.

In this case from page 10 it is clear they are wired in Star.

This means (if the appliance has been designed to do it, as is the case for many induction elements) L1, L2 & L3 can be bridged together and all powered by the same phase, and everything "Should" work.

There are two major issues that can come up with doing this:

• Current now all goes on one phase, If it is the biggest 9.0kW sauna, that would require 40Amps of capacity. A lot to provision in NZ where many houses have a single phase 60A pole fuse. Smaller 4.5kW one might be easier at 20Amps.
• Current on the neutral goes from near zero, to the same as what is being drawn from the Phase (up to 40A). If the internal neutral wiring hasn't been sized for this it will overheat and fail.
• Earth wiring may also be potentially undersized.

The above issues mean this is not really a DIY job. A sparky needs to access your power supply to see if it can handle the load, and the appliance needs to be taken apart and the sizing of the internal neutral wiring verified for suitability.

it is possible, but the limiting factor will be the capacity in the house to actually supply the power required.

For example if you were to convert the 9kw unit to 1 phase, that would be a 40A supply, basically another oven. Considering most houses have a 60A supply this would leave you no spare capacity for the rest of the house.

We won't even touch on modifying an appliance and the invalidating the Sdoc, it just turns in to a mess really quickly.

The way I read that diagram there is no modification required to run it on single phase. Perhaps I'm reading it incorrectly.

You just wire up the terminals on the right (N & K) and the earth to your single phase supply. Only one heater element is connected and thus you only get one third of the heat. Bearing in mind the specs show 2 kw when 400 volts is supplied to the element. So you'd probably get a shade over 1 kw of heat.

If you want all elements to produce heat you have to wire it to 3 phase power, otherwise you have to modify it which I suspect is not acceptable.

Regarding my other comment I had missed that this was the 6.0kW unit. 6kW on 230v single phase is roughly 26 A. Tight to provision, but more likely to be workable than 40A. Electrician might want to put in a main breaker to protect the pole fuse.

Technofreak:

 

The way I read that diagram there is no modification required to run it on single phase. Perhaps I'm reading it incorrectly.

 

You just wire up the terminals on the right (N & K) and the earth to your single phase supply. Only one heater element is connected and thus you only get one third of the heat. Bearing in mind the specs show 2 kw when 400 volts is supplied to the element. So you'd probably get a shade over 1 kw of heat.

 

If you want all elements to produce heat you have to wire it to 3 phase power, otherwise you have to modify it which I suspect is not acceptable.

 

I think N & K is optional control wiring.

Getting 1/3 of the heat likely won't be sufficient for the appliance to function as intended, Typically to do that just L1, N, E would be wired up.

Because of the star configuration the element would see the same voltage. So output per element would be remain at 2kW.

Issue with potentially undersized neutral doesn't go away with only one element connected. Still best to check it is appropriately sized.

Also it is unclear if how that control system works is, and if all elements get switched at the same temp, or they get switched in a sequence.

Reading the manual it does seem that the 60NB can be wired in single or 3 phase configuration, but before you commit, you need to work out if your switch board/power supply can support that.

6Wk at 230v is 26 amps. There may or may not be enough surplus capacity on your supply to support a new 26 amp load. If there is insufficient capacity you will be forced to upgrade the power feed to the premises and if you're going down that raod, then the difference between upgrading single phase or 3 phase is small. 

This is the same issue people installing kilns at home run into. 

tripper1000:

 

Reading the manual it does seem that the 60NB can be wired in single or 3 phase configuration....