I have a generator I want to install in a semi-permanent postion, ie. to avoid trailing a cable throught a window or summat, I want to have a dedicated (maybe different coloured?) socket for it in the lounge that I can connect to the generator on the outside. On the ouside wall, I envisage something like this:
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preferably, a less expensive version - is there one?
Also, I'd like to box the generator in, in order to sound-proof it as much as possible. Obviously it will still need to 'breathe'.
Presumably, the dreaded Part-P comes into effect here, but other than that, any ideas on this?
What's the generator for - presumably for emergency power in a power cut?
By far the safest way is to do what you appear to be doing - to have a dedicated outlet and to unplug appliances from the mains and plug them into that when necessary. If you envisage wiring it into the consumer unit, with some sort of change-over switch, it gets a lot more complicated - and expensive.
I don't know for sure whether Part P applies to what you're doing - but who cares?!
What sort of generator is it - Diesel, petrol, 2-stroke, 4-stroke - and what's its capacity? You will need to provide your own earth, using an earth spike. If you're planning to run any sensitive electronic equipment off it you need to make sure that it provides a decent waveform and has good voltage control. If you're planning to run a central heating boiler with electronic ignition, you'll probably need to make sure that neutral is tied to earth rather than floating.
The sort of external connector you suggest is also used on caravans. You may get one (and a mating in-line socket) cheaper from a caravan dealer. Or, if you're building a waterproof enclosure for the generator, why not just have a cable coming through the wall with a 13A plug (or whatever) on the end, to plug into the genny?
It would be better to have a break-before-make changeover switch fitted with an external weatherproof plug mounted to a wall in a convenient location so that you can power the consumer unit from the generator.
Definitely needs Part P and probably an electrician.
Thanks. It's a 4-stroke petrol, only 900W - I wasn't planning on running anything special off it, just a light, the fan for the gas fire's flue and... would the TV run off it? And yes thanks, a bit of googling has revealed caravan connectors. They are a much more reasonable price.
I was wondering about earthing. Is there anything special about and earth spike, or will any old metal rod in the ground do?
Surely that depends on the capacity of the generator? Unless it can power the whole house, it's best just to plug selected critical items (CH boiler, freezer, emergency lighting, TV?, etc.) into it.
Depends on the telly - how much power it takes, and whether it has a much larger surge current when you first turn it on.
They are, of course, lower capacity than the one you cited - but perfectly adequate.
I use one of these:
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needs to go a fair way into the ground. There *are* ways of measuring the impedance of an earth connection - but they're beyond the average DIY-er, so stick one of these into moist soil, and hope for the best!
It also opens a new can of worms with earthing. If the house is already TT is is relatively straight forward, however with a TN setup you are going to need a relatively elaborate switching setup to introduce the required levels of RCD protection and to switch to a local earth as well.
I'm out-of-my-depth here, but when there is a E provided by the supplier, is there any reason why we can't continue to use the existing mains supply earth ( even though we've switched over the L+N conductors ) in the event of a power failure?
Then at the generator, we have the N tied to the frame, and then we run 3 cores to the house, L, N, and a E from the frame-N bonding point to the house main earth point, so the generator's earth is the same as the supply earth ( give or take voltage drops along the generator cable ).
In otherwords, export the supplier / house E to the generator.
Or can we not assume supplier E integrity in the event of failure? ( like a JCB went through the cable ouside the house... )
Yes, that is expressly forbidden. Mainly because you have no guarantee that the earth will remain working during a failure.
That would be one example - if you think of some of the many reasons that you may lose power (broken cable, overhead line down etc) then the thinking behind this should be apparent. Also note that in the case of modern style PME installations the earth integrity depends on a combined neutral and earth conductor that comes right to the house before separating.
Hence for the generator you need it as you described but with the addition of a local earth rod. You would also need TT style RCD protection (i.e. on all circuits - not just sockets) since the earth fault impedance will probably be too high to allow normal operation of circuit breakers under fault conditions.
Their customer care is cr*p, I phoned them 2 years ago wishing to buy one and was promised a return call as they could not deal with me at the time, then phoned a week later as I had not had a call only to be told that yes they had my details and would call me back, I'm still waiting. Bought one elsewhere and was quite happy with it.
Umm well, a sensible person would switch off the unnecessary equipment. Plugging a CH boiler into a generator is non-trivial given how most installations are performed. Having power via the CU is easier.
Besides what sort of lame generator are we talking about here, a 650W "suitcase"?
A 5-6kW generator which should be all anyone needs for a domestic emergency supply will hardly break the bank.
voltage and frequency is almost impossible to achieve in practice with a small generator. Even the backup generators that Scottish & Southern use to supply emergency backup to individual premises (around 8 kVA) are very erratic with regard to maintaining voltage and frequency even moderately stable.
In general terms you should accept that these things are fine on a resistive load. Anything else you use at your own risk.
CH programmers are apparently very common victims. I'd certainly take my modern programmer out of circuit and make a connection to the CH boiler direct -- it has an ancient control box full of mechanical relays. Fluoresecent lights can be unbearable if the frequency drops and who knows what it will do to the life of your CFLs. Sensitive electronic equipment is best given a miss. And how many appliances now are devoid of electronics. Your Dualit toaster is immune :-)
The whole problem needs a lot of careful thought.
What's the risk of power failure? What's the record over the past ten years in that area?
What's the probable duration of power failure? Again, what's the longest outage over the past ten years been?
What do you actually NEED in the event of power failure of a variety that's a reasonable possibility? Do you actually NEED power to the freezer (it'll be OK for at least 24 hours and probably much longer if you don't disturb it) Can you provide means of heating, lighting and cooking by means more suitable than electricity in an emergency? Paraffin lamps will stay "at the ready" for years without attention. A Calor gas cooking ring takes no space and the high pressure ones are excellent. To what extent do you NEED the whole house heated? How many of your needs can be provided at 12 volts DC (and don't forget that we all have one or two large (albeit very inefficient) generators capable of providing that -- and with a little careful planning, capable of providing it at large current draws as well.
For me, the important needs can best be met by
several UPS units -- one of them weighing more than 50kg; power supplied from vehicles -- one of which is a big LandRover with an Optima battery
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has more than proved its worth -- the vehicle used to go through a battery every couple of years. These batteries are horrendously expensive but brilliant.
Calor Gas for cooking and heating -- coal for a longer outage.
Paraffin for lighting
The deep freeze will keep things for at least two days and in any case, outages are more likely to take place in cold weather and the freezer isn't inside the house but in an annexe which won't be heated in the event of an outage.
Remember that no backup is of any great value unless it's available immediately the problem arises :-)
It has to be planned for - obviously. I've rewired my CH so that it's powered from a 13A plug near the boiler , rather than from an FCU.
The OP apparently has a 950w generator - which *certainly* wouldn't power the whole house without *serious* risk of overload. I have a 2kW Honda inverter-based jobby - which is adequate for all the essential things - but I still wouldn't wire it into the consumer unit.
The total project cost would not be trivial by the time you've got the necessary change-over gear and suitable earth provision.
Depends on the genny! I've looked at the output of my Honda inverter-based jobby on a scope, and it's rock steady when you suddenly change the load - all you hear is a change in engine note.
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