3-Phase Supply ...

[Sinbad]

Stoned more like.
Three phase uses a common neutral.

 

[Seriously]

Stoned more like.
Three phase uses a common neutral.

As I said go educate yourself. You ONLY use the neutral for single phase connections to a three phase supply. Your home Supply is one phase of a three phase supply and a neutral. Three phase motors and equipment do not need or use the neutral. Go educate your self. Google is your friend in times of crisis!

 

[Username:]

As I said go educate yourself. You ONLY use the neutral for single phase connections to a three phase supply. Your home Supply is one phase of a three phase supply and a neutral. Three phase motors and equipment do not need or use the neutral. Go educate your self. Google is your friend in times of crisis!

You are both correct.

For three phase loads you only required the three phases, connected as star or delta.

For single phase loads on a three phase supply you need to have a neutral return for each phase , taking lighting supply where you supply highbay lights in a factory you will need a 7core cable , 3 cores for each phase, 3x neutrals for each phase and the earth.

 

[Shellyb1]

Normally the Eskom three phase supply is 220V between the neutral and any of the three phases. Thats why in Industries it's possible to balance the 220VAC loads by sharing equal loads between the three different phases and neutral. So you just connect between the neutral and any phase. Three phase is better thought so what and why do you want to change?

I am having an inverter installed. Installer didn't know it was a 3-phase (oversight on their side) and said that he can convert it to single phase.

I don't have any appliances that use any major voltages above 220v and for my needs am not phased (pardon the pun) by having a 3 vs single phase supply.

The plan is to put all the essentials (lights, plugs, gate motors) on the solar/inverter and only put some non essentials (pool motor, solar geysers [small draw but not essential to run]) on another Eskom supplied phase.

Is it as simple as that?

It would cost me extra to get a 3 phase inverter and all the extras and trying to make do with what I can. Also don't want to put my family, home and appliances at risk if it's a make shift job.

 

[Sinbad]

Ok I gets it. A three phase motor can run without a neutral but distributing phases to single phase loads (like household appliances etc) need the neutral.

 

[Seriously]

Ok I gets it. A three phase motor can run without a neutral but distributing phases to single phase loads (like household appliances etc) need the neutral.

Now we speak the same language!

 

[Sinbad]

Now we speak the same language!

So for a home three phase application you better get the phases synced properly else your neutral will be carrying too much current? ;-)

 

[Seriously]

I am having an inverter installed. Installer didn't know it was a 3-phase (oversight on their side) and said that he can convert it to single phase.

I don't have any appliances that use any major voltages above 220v and for my needs am not phased (pardon the pun) by having a 3 vs single phase supply.

The plan is to put all the essentials (lights, plugs, gate motors) on the solar/inverter and only put some non essentials (pool motor, solar geysers [small draw but not essential to run]) on another Eskom supplied phase.

Is it as simple as that?

It would cost me extra to get a 3 phase inverter and all the extras and trying to make do with what I can. Also don't want to put my family, home and appliances at risk if it's a make shift job.

YES!

I do not understand what he wants to convert thought?

If I understand correctly you have a 3 Phase infeed from Eskom but are getting a single phase inverter from Installer? Then no problem if he connects it between a neutral and the correct phases for operation of the specific phase you want to back up and connect to solar. Just do never connect a three phase device with two phases on Eskom and one on your inverter output. If the installer is a qualified electrician should know what he's doing and have to sign of a electrical installation certificate.

 

[Shellyb1]

YES!

I do not understand what he wants to convert thought?

If I understand correctly you have a 3 Phase infeed from Eskom but are getting a single phase inverter from Installer? Then no problem if he connects it between a neutral and the correct phases for operation of the specific phase you want to back up and connect to solar. Just do never connect a three phase device with two phases on Eskom and one on your inverter output. If the installer is a qualified electrician should know what he's doing and have to sign of a electrical installation certificate.

Thanks. Yes, qualified electrician. Just want to make sure he is not trying to take a short cut.

Thanks for the input.

 

[ellyally]

Is it possible to change from 3 phase supply to single phase? I have a reasonable large house but no major appliances (aircon) only a pool motor.

What would I need to change to run on single phase?

I know nothing of electrics etc, but had house rewired a while back, it was on 3 phase, geyser on one, stove on another, rest of house on the other. Electrician said it wasn't needed nowadays and put everything on one. Don't know what is meant by balancing etc? As said, know nothing of these things so not sure if right/wrong but it passed checks and got certificate.

 

[itareanlnotani]

I am having an inverter installed. Installer didn't know it was a 3-phase (oversight on their side) and said that he can convert it to single phase.

I don't have any appliances that use any major voltages above 220v and for my needs am not phased (pardon the pun) by having a 3 vs single phase supply.

The plan is to put all the essentials (lights, plugs, gate motors) on the solar/inverter and only put some non essentials (pool motor, solar geysers [small draw but not essential to run]) on another Eskom supplied phase.

Is it as simple as that?

It would cost me extra to get a 3 phase inverter and all the extras and trying to make do with what I can. Also don't want to put my family, home and appliances at risk if it's a make shift job.

Hi Shelley, yes thats fine.

Your household stuff is all running off one phase anyway.

Typically what happens is that 3 phase comes in, and each phase is split off to supply separate loads - eg lighting may be run off one phase, plugs on another, heavy loads on another (or separately wired to different phases if you have multiple heavy loads), and 3 phase equipment like a old school 3 phase cooker, or a 3 phase pump will be connected to all 3+neutral.

It uses less wire to supply 3 phase @ 20A (for 60A total), than to supply 60A, so its quite common to have 3 phase from the supplier side (Eskom / Muni). 3 phase is better to have imho, as single phase loads can only overwhelm one phase, rather than all of them.

Sounds like they're just going to supply backup? to one phase.

Make sure that the wiring at the switchboard is hooked up correctly, and they only connect one phase to the battery backup inverter. I would be slightly concerned that they didn't identify it was 3 phase in the first place though, that makes me slightly cautious about your supplier.

The first site visit they made to take a look at your potential install, they should have brought that up and asked you how you wanted to go forward. That they didn't, and are only telling you now is a warning sign.