I have a question for anyone out there with the knowledge to answer...
Myself and my business partner are both time served registered electricians and are doing a lot of inverter installs at the moment due to the load shedding issues we're experiencing.
Firstly, we are battling to find any decent supplier of inverters (pure sine preferable), so if anyone can point me in the direction of someone with a quality product i'd be interested to hear...
2ndly, the kind of install we are doing is a fully automated one.
Let me explain a bit...
The client supplies the UPS (for want of a better term...an inverter battery system is basically just that anyway...)
We install it as near to the mainboard as possible, and wire it into the mains with control and protective circuitry so that in the event of a power failure, only the critical circuits that the client requests will be powered off of the inverter/ups.
We wire the inverter so that when mains is on, the earth leakage supplies all of the plug circuits (and others that are run through it) as per normal.
When the mains fails and the inverter kicks in, it too runs through the earth leakage, supplying the critical circuitry, which is usually the tv and router plug circuits and the fridge, and possibly a lighting circuit or 2 (obviously the inverter setup is spec'd correctly for the amount of load required to be run).
The pure sine inverters are a dream, and run like this perfectly...however...the modified sine wave inverters do not run through the earth leakage.
They trip the earth leakage as soon as they come in, and you cannot reset the earth leakage on a modified wave.
So the only option is to wire the critical circuits off of the earth leakage.
Now how does this hold true according to the current regulations, where they state that all plug circuits should be protected by an earth leakage?
Do i need to tell the client that he must supply a pure sine wave inverter or his installation will not be compliant, or do the regs make allowance for this kind of install?
I realise that a UPS unit is designed to plug into a plug socket (thus excluding it from a CoC as it is not part of the fixed wiring), but if my client is asking me to automate his system so that he can have lights and usually 2 different (lounge and kitchen) plug circuits running off of his UPS in the event of a power failure, then how am i supposed to proceed?
Could someone tell me what the current regs have to say about an inverter as an alternative supply?
If a generator can be connected through your mainboard by means of an ATS, then surely so can a UPS/Inverter system.