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Generator safety

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Weaver:
I keep repeatedly telling my dear wife about electrical safety. Our petrol generator is out in the shed. Unfortunately it just puts out its power by being plugged straight into a three pin mains socket. If she were to do so and turn it on she could electrocute any electricity board staff working on the line who think the power is off, or power all the houses in the village. So I tell her again and again that the entire house must first be disconnected from the external supply and I require her to show me that this has been done. However I would like to have more layers of protection against mistakes.

The discipline currently is that I have to be given the 100A main house fuse link first, so my possessing this proves to me that Janet has disconnected the house from the external feed. Then she is allowed to turn the generator on. This only works provided it is not forgotten.

I have an idea or two, but none that are foolproof. The simplest one is to lock the generator up in a box and only I have the key but this is bound to go wrong. I have other ideas too which are not complete and not robust enough.

Can anyone with a brain think of anything really foolproof ?

d2d4j:
Hi weaver

We use Datacentre power auto switches, which have dual power feeds in, and also switch isolation to switch to secondary power feed (say UPS or additional power feed), so the entire power circuit feeding anything attached to the outputs remain normal.

These are very very expensive and mostly not available in the UK

We did not wire these, a fully qualified electrician wired them. Mains power frightens me.

My best advice is to speak with an electrician

Also, if I understand your post, I do not think you are legally allowed to touch that 100A fuse

Many thanks

John

Weaver:
Regarding the 100A fuse. This is just an OTT safety measure and is not the only way of doing things. The electricity board man who came to wire the house up to the grid explicitly left the seal off the 100A fuse so that we could disconnect things as at the time I was indeed doing the entire house from scratch as it was nearly a ruin. I used to be able in those days. I chopped lots of logs and chainsawed lots of tree trunks 20 years ago. I seem to remember hearing something to the effect that the law in England, at any rate, has changed in subsequent decades and nowadays you are supposed to get an electrician to do some things in your house. I am not sure we have any laws in the Highlands and Islands :-)  :o  (Apart from planning permission, thieving, drugs and speeding laws concerning which certainly do exist.)

We don't need to use the 100A fuse of course. Could just throw the switch at the main box. But I do that so that I have an absolute guarantee that the right thing has been done. If I am holding the fuse the house can not possibly be connected.


One idea that had come to me was to make up a cable from the generator to a wall socket which had an in-line break in it. This break is bridged or not by plugging that same 100A fuse, having been removed from its usual place, into a second fuse holder socket purchased for the purpose and wired in-line.

This is the best plan that I have been able to come up with so far.

siofjofj:
The most foolproof method is to put a changeover switch (eg https://www.tlc-direct.co.uk/Products/CGM125CS.html) between your electricity meter and consumer unit (job for an electrician to install really). These are basically double-pole-double-throw switches, with the common terminals connected to the house, one set of switch terminals connected to the incoming mains and the other set to a suitable wall mounted male plug (eg https://www.tlc-direct.co.uk/Products/GW240slash16slash3A.html) which can be connected to the generator with a suitable cable. With this arrangement, it is impossible to back power the grid from the generator.

I assume you are currently using a lead with a 13A male plug on both ends to connect the house to the generator? These are generally referred to in the trade as 'widow makers', since with one end plugged in the other has live exposed pins. Another advantage of the above arrangement is that your generator lead will have a male plug on one end and a female socket on the other, so nothing live is ever exposed.

Weaver:
As for 'widow makers' I can't remember what the lead is currently. If I had seen such a thing, plug to plug, it would have been gone as quick as you like. :-)

I am grateful for those tips! The difficulty is that the consumer unit is absolutely nowhere near the generator, generator is in a shed because of noise and carbon monoxide. (Has some ventilation so the generator can get more O2 in.)

I am quite a stickler for electrical safety, my wife having had a washing machine burst into flames because the motor jammed while I was out at work when we were in London, my friend’s house in West Yorkshire ruined by a similar appliance fire, a fire in the optics laboratory at university when my mains-powered handheld mini red-light torch melted and took out all underfloor wiring, the university's chemistry department burned down after a calculator caught fire, one of my best friends burned a hole right through his finger by shorting the mains out with it, my mother got an electric shock due to 1950s wiring when I was young and my sister burned out a wall socket in her bedroom. So I am always moaning on about RCDs, correct fuse ratings, earthing and so on and pestering my wife to keep a comprehensive range of smaller-rated varied fuses in stock.

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