Saturday at home, installing an inverter

[Tonye]

Nice looking installation, your trunking is neater than mine

Looks like a lot of essential circuits in the back-up sub-DB.

Thanks Andy,
the trunking is quite expensive but comes with all sorts of inside, outside bends & end caps.
Saves on having to mitre bends.
I have moved quite a few circuits. 3 light circuits & 5 plug circuits.
Client currently has 70x 50w down lights. This is being changed to 4 watt LEDs.
The plug circuits are feeding the following
Study ( small PC, Modem router, inkjet printer & a laptop.
Living room ( Led Tv, Dstv decoder & 2x table lamps)
Dining Room ( two table lamps)
Formal lounge ( 1x standing lamp, 1 table lamp)
Main bedroom ( 2x table lamps, 1 x led Tv)

The client is aware that when running in inverter mode, he cannot run everything simultaneously
but still has the convenience of being able to run most of his plug & light circuits.
Obviously when running from mains, there are no restrictions.
The system has been designed to allow an upgrade to a larger system if required.
When running essential items the changeover can be left in inverter mode to supply uninterrupted power supply
in the event of power failure.
Fridges, pool pump, air cons, microwave, washing m/c, dishwasher, geyser, stove etc have been left on Main DB.
I was fortunate that the circuits I moved did not include the above.
I was going to do a total changeover at the main DB, where the client turns off high current items prior changeover
but the Main DB is three phase and did not want to fiddle whith a 4 pole changeover with bridged connection on inverter mode. ( not sure if this would pass a COC)
One problem I had was when tracing neutrals for the lighting circuits, I found one light circuit that even after disconnecting all the neutrals still powered lights in certain lights. Obviously a major neutral to earth fault. Two of these lights are large chandeliers which can be reached easily.
I have informed the client to contact the electrician who issued the COC to rectify the problem.

[AndyD]

Thanks Andy,
the trunking is quite expensive but comes with all sorts of inside, outside bends & end caps.
Saves on having to mitre bends.

My trunking was recycled second-hand It was all I could find at the time and the installation was in my own office so I wasn't too worried.

I have moved quite a few circuits. 3 light circuits & 5 plug circuits.
Client currently has 70x 50w down lights. This is being changed to 4 watt LEDs.

Sounds sensible. Trying to accomodate 50w halogen downlights would be pointless and expensive. Every installation is different, you installed your inverter at the main DB and separated 8 circuits out into a back-up Sub DB, I installed my inverter very similar to installing a UPS where it supplies only my office circuit. The other supplies to the kitchen and lounge are run as temporary extension leads. This was just to keep the complexity down and to allow it to evolve easily for future, if it had been a customer installation we'd have also installed a subDB specifically for back-up and marshalled all the apporopriate circuit into there.

One problem I had was when tracing neutrals for the lighting circuits, I found one light circuit that even after disconnecting all the neutrals still powered lights in certain lights. Obviously a major neutral to earth fault. Two of these lights are large chandeliers which can be reached easily.
I have informed the client to contact the electrician who issued the COC to rectify the problem.

Yeah, pre-testing the circuits beforehand is critical. The lighting circuit probably has a borrowed or crossed neutral with another circuit, if it was an N-E insulation fault it should have shown up under normal testing if a CoC has been recently issued.

Total cost for this installation R22000.00 excl

I think your pricing is pretty good. I'm not sure what inverter you've used but I know if I was quoting to install the setup I outlined at the beginning of the thread it would be around R26 - 28K including labour. You've installed a subDB and changeover switch but I've got extra battery capacity and a larger inverter so it's swings and roundabouts.