Mains changeover switch to generator backup

[Mike Humphrey]

The regs say it is. After all, the power cut could be caused by the cable being cut just outside your house, which would cut the earth as well. Or even the cable being deliberately removed (to replace it, for example).

The setup I described had one circuit fed from the generator not passing through the CU. In this case you would need another RCD (or RCBO). If the generator supply passes through the CU RCD, then you don't need to add another one. But you do need RCD protection on every circuit, as your generator is TT earthing - if your CU only has RCDs on some circuits, you either need to add more RCDs/RCBOs or put a time delay RCD in front of it.

Yes, that's the downside of putting everything behind the changeover switch - you can't see when the power comes back.

Mike

[John J]

Perhaps worth mentioning the input DC current (ignoring efficiency/losses) of a 12 supply from a battery will be around 20 times greater than that delivered to a 240 volt load - not something a typical battery will sustain for long. Hence my preference for a generator.

[tony sayer]

I've been told that the transmitters at Emley Moor are on f*ck off size UPS units to keep on air whilst the gennies start up!...

[ARW]

So are the essential circuits at Doncaster Royal Infirmary.

[ARW]

My Dad would fork out for a 7/8kW genny with electric start and a changeover switch tomorrow. The inverter was all my Mum would allow him to have and she was not happy about that. She cannot see the need.

Your point about DC losses and the battery not lasting very long are noted. Thank you.

However my parents have two cars sat in the garage next to the inverter that they can use top up power up if needed. It was never a 24/7 solution but it could run the CH for a few hours a couple of times a day and keep a couple of table lamps on for several hours before they needed to top up. As they are not in rural Aberdeenshire hopefully they will never go 3 days without electricity.

For some reason your post has reminded me that I am going to have to get laminated instructions how to use the inverter printed off for them or for a neighbour to be able to do it for them. My Dad is getting a little forgetful and my Mum has no interest in it.

Cheers