Putting a 3-pin plug on my boiler.

[Avocet]

Is there any reason why I shouldn't do this? We have an oil boiler and the electrical feed comes up behind the work top and into one of those fused "sockets" with no holes in them for a plug. (Dunno what their proper name is)! We also have a notoriously flaky electricity supply. Today, the power went off in the morning (when I was in the shower with shampoo all over my head!) and came back on at about 17.00. I have a small genny (about 650W) which I fired up and ran the fridge and freezer (had to take turns, it didn't like it when they both cut in together) and computer and router. Anyway, although it wasn't that cold today, during the winter we really suffer from not being able to heat the house or water. Today, I disconnected the boiler wire and put a 3-pin plug on it. The genny coped fine.

I'm worried about fatiguing the solid copper wires leading to the fused "socket-that-isn't" each time I disconnect the boiler to run it of the genny. Next to that "socket", is a real one, which the wire will reach. Can I just permanently put a 3-pin plug on the wire and plug it into the wall socket so that I can unplug it and plug it into the genny when we have our next power cut?

 

[RF Lighting]

As long as the fused connection unit (that's it's proper name) supplies all your heating control circuitry there is no reason why you shouldn't replace it with a single socket and connect a plug to the supply flex.

If the supply flex feeds only the boiler and not the room stat and zone valves etc (assuming you have any) then it may be unsafe to do so with a risk that the pins on the plug could come live if something else it putting mains to the boiler when you are on the grid supply.

 

[ericmark]

In the main there is no problem running a boiler from a generator. Some have an issue with earthing but most will work OK.

The idea of unplugging from mains and plugging into generator is likely the safest way as impossible for both supplies to ever connect together.

In one farm he had a mains consumer unit that fed directly non essential items. It also feed a 32A socket and there was a second consumer unit feeding essential supplies feed from a wandering lead with a 32A plug on it which would normally be plugged into the 32A socket.

When the power failed he just unplugged from socket and plugged into generator instead. It was impossible for generator and mains to ever connect together. It also meant if his generator was in for service or repair he could easy hire a replacement.

The point was however some one was always at the farm to swap the plug. With other companies they go for the UPS as not always there to swap plug.

I was rather surprised my freezer failed and I lucky had a spare but it needed moving to where it could be plugged in. This took some time around 4 hours from one freezer failing to other freezer being ready to take the food. Food from bottom of failed freezer was OK but by time I reached the last draw at the top food was clearly starting to thaw. It said on the paperwork with freezer it would last 8 hours without opening door but in real terms it did not last 4 hours.

It would seem there are some test devices they put in freezers which show if it has failed then been started up again. Since when power is off you don't open the freezer unless like my new one you have a temperature readout you have not a clue how warm it got.

 

[RF Lighting]

When I eventually get round to sorting my mains out at home I'm planning to install a three phase dist board using L1 for any essential circuits like the heating, a few LED lights and the living room telly etc, and L2 and L3 for non-essential circuits.

I've not decided yet if I'll use a manual change over switch or build an ATS, but either way when mains is availible, L123 will be linked together, and when only generator is availible only L1 will be powered.

I've got a 2kVA genny in the garage which is not big enough to run the whole house.

 

[ericmark]

I have a small genny (about 650W) which I fired up and ran the fridge and freezer (had to take turns, it didn't like it when they both cut in together) and computer and router.

I have monitored my fridge/freezer and freezer power.

Samsung RZ80 Freezer Idle 11W run 58W Defrost 276W.
Samsung RL60 Fridge Freezer Idle 9W run 53W Defrost 215W.
With both used a plug in meter which recorded Max Watts which was only reached when on de-frost cycle.

My mother however has a very small 30 litre freezer with no de-frost function run 28W but start 973W.

A old Hoover fridge/freezer run watts 82 but start 2259W
A smaller fridge/freezer at sons house was 170W run did not record start.
A small freezer as sons was 153W run and 719W start.
Power factor correction was as low as 0.75 with the old freezers.

The measurements were made with the idea of working out if it was worth changing an old unit to save power and it was not the cost of replacement over 7 years considered as normal life was not enough to make it worth changing.

But the single phase motors in the older units have a massive start amps. They also have built in overloads as if it tries to start before the pressure has dropped it will stall. Trying to run a fridge or freezer from a long extension lead can cause problems where the overload is being repeatedly tripped and in the end they fail. Likely it is one of the major reasons for them to be thrown out the over load has failed due to repeatedly being tripped.

The two Samsung models I have quoted has 3 phase motors and are started using an inverter the inverter/motor package has a 10 year warranty although that does not include the rest of the unit. The whole idea is if you remove the overload device you have removed a major cause of motor failure. This is as I have said more of a problem when using extension leads most freezers and fridges say not to use extension leads in their instructions.

You clearly have the same problem with a small generator. The fridge and freezer start current is the problem rather than the run current. Often having one motor running actually helps start the second one.

But you have to consider the damage being caused to the overload trying to run them from a small generator. At the cost of the Samsung clearly best option is a larger generator to get the start amps required. Only if an existing freezer or fridge was to fail would it be worth replacing with an inverter model.

The gas fridge with electric option uses nearly twice the power of an electric only model. However it does not have the start amps problem and can be switched to gas with a power failure they even run on 12 volt.

The peltier fridge is worst of them all it uses 4 times the power of a electric motor type. The only advantage is does not matter what angle it is used at or how much it is shaken so used as cool boxes in cars.

Gas fridge in a caravan uses around 200W on mains which is higher than any motor type but no start amps.

I don't know how often you lose power but if quite often I would say you need a bigger generator. Some of the inverter generators can be run in tandem worth considering. With inverter generators the speed varies with load so they use less fuel but not sure how they would handle the start amps. It is the same with other generators some will just cut out if you try to draw too much others can be overloaded and can burn themselves out. It really does seem to be pot luck which you get.

 

[dhutch]

Two consumer units and a change over switch (rather than a flying plug/socket, ideally....) would be the neat way to do it.

But as said, as long as there not chance of the 'boiler' back feeding power onto the pins, and or some wired interlinking between the boiler and the controls, it should be ok.

Obviously fuse the plug the same as the fused connection unit.


Daniel

 

[JohnW2]

As long as the fused connection unit (that's it's proper name) supplies all your heating control circuitry there is no reason why you shouldn't replace it with a single socket and connect a plug to the supply flex. ... If the supply flex feeds only the boiler and not the room stat and zone valves etc (assuming you have any) then it may be unsafe to do so with a risk that the pins on the plug could come live if something else it putting mains to the boiler when you are on the grid supply.

Indeed - and that is precisely what I do. All of the heater control circuitry (including boiler) is powered via a 13A plug/socket, there being an adjacent genny-supplied socket into which it can be plugged if necessary. I used to have a manual changeover switch, but that was so large and clunky that some members of the household found it difficult to operate - and a plug/socket arrangement obviously gives total reassurance that there can never be any grid/genny interconnection.

However, as you say, it's only guaranteed to be safe if all of the heating system is powered via the plug/socket.

Kind Regards, John

 

[JohnW2]

When I eventually get round to sorting my mains out at home I'm planning to install a three phase dist board using L1 for any essential circuits like the heating, a few LED lights and the living room telly etc, and L2 and L3 for non-essential circuits. ... I've not decided yet if I'll use a manual change over switch or build an ATS, but either way when mains is availible, L123 will be linked together, and when only generator is availible only L1 will be powered. ... I've got a 2kVA genny in the garage which is not big enough to run the whole house.

I also have a 2kVA genny in the garage.

As described above, my entire heating system is powered via a 13A plug, which can be plugged into an adjacent genny-only socket if required. The genny supply is hard-wired to a number of ‘genny-only’ lights (now mainly LEDs, originally were baby fluorescents) scattered throughout the house (and usually left switched ‘on’) plus a few strategically-placed ‘genny-only’ sockets. If I fire up the genny, all those ‘genny-only’ lights come on, enabling me to see what I’m doing when I plug the heating into the genny supply socket and plug anything else crucial (TV?!) into one of the genny-only sockets. Not as elegant or simple as a ‘changeover’ system using the house’s normal circuits, but it enabled me to be totally confident that all of the genny-supplied ‘fixed wiring’ was totally separate from the normal house wiring. The garage has a battery-backed up emergency light, so I can see to start the genny!

Kind Regards, John

 

[Aragorn84]

Is your electricity that unstable that you need to goto all of that effort?

I mean i guess i'm used to living in a town, but i dont really remember the last time we had a power cut, certainly theres never been a situation where i've thought "damn, if only i had a genset in the garage"...

Maybe if you lived up in the highlands of scotland or something i could understand it, but middle england?!

 

[JohnW2]

Is your electricity that unstable that you need to goto all of that effort?

Not since I went to that effort - Mr Murphy's Law worked well

I mean i guess i'm used to living in a town, but i dont really remember the last time we had a power cut, certainly theres never been a situation where i've thought "damn, if only i had a genset in the garage"...

Albeit it in 'Middle England', I live in a pretty rural location, with most electricity supplies overhead. When I first moved here, nearly 30 years ago, power cuts were common. In particular any flash of lightning within a few miles was at risk of taking out the supply, and it was not uncommon for it to be an hour or three before it came back - I can but presume that automated systems often failed to 'reset'. It is pretty frustrating to have gas (LPG in my case) heating, but to be cold because the electricity supply has failed! I therefore eventually 'went to all that effort' - and, needless to say, I've only had to use the genny 'in anger' a very small number of times since

Of course, some people believe that, because of the anticipated changes in the supply/demand situation, power cuts will become a more common feature of life, in urban as well as rural settings, before too long!

Kind Regards, John

 

[dhutch]

I'm 27 and moved out 10 years ago, but in my time the number of power cuts at my parents dropped hugely.

Winter when I was a kid required a torch, candle and matches in all the major rooms and for a about 2-3months of the year it wasn't really practical to keep the microwave clock telling the right time, outages would often be for a few hours, and the heating timer had to be locked to 'always on' else the underfloor heating missed economy 7 as it would loose hours.

They now have a power failure maybe once/twice a year, and typically the powers back on within minutes.


Daniel

 

[SimonH2]

I recall there were more power cuts as a kid - but then I believe the miners were on strike I remember the posters in the local Electricity Board shops giving the power cut rota.

Where I used to work we had a fair number - we were on the end of a long chain of overhead connections. I recall they tended to fall into categories :
Short - power back on in a few seconds to a minute or two.
Medium - around 90 minutes give or take a few.
Long - some random longer period.

I concluded that these corresponded to automatic or remote control reclose, on-call engineer needs to manually reclose*, or some "hard fault" respectively.
* This was around the time there were "management and personnel changes" in the local DNO, and I suspect the engineers were unofficially not fixing faults in under 90 minutes to avoid management expecting them to do it quicker in future.

But where I work now we have a generally good supply - it's all underground plant from a 132/33/11kV substation we can almost see from the office window (we can see the 132kV circuits dropping into it's yard). We still have power cuts - the last ones were due to mechanical faults on the 132kV circuits (broken earth/neutral wire dropping onto phase wires).

But I do recall having long power cuts at home over the years. Round here there generally isn't that much redundancy at the 415V level. So when there's a cable fault, or substation fault, it can be a while before the power comes back on.
Or I know of several faults locally (affected friends) that have required a temporary generator - these obviously take time to be delivered and plumbed in.

 

[plugwash]

anyone know long does a power cut have to be expected to last before they truck in a generator.

 

[JohnW2]

anyone know long does a power cut have to be expected to last before they truck in a generator.

westie would

Kind Regards, John

 

[bernardgreen]

anyone know long does a power cut have to be expected to last before they truck in a generator.

Never for a domestic user unless you are a priority customer. Home dialysis and similar equipment can make you a priority customer. Even relying on a domestic sewer pump did not make us a priority customer. (*).

In the early days (1980's) we had a few cuts but as the village sewage pumping station was on the same supply those cuts were quickly noticed and dealt with. Then complaints about voltage drops when the pumps cut in led to the pumping station getting its own 11kV feeder and transformer. So our supply was no longer monitored and cuts were longer, rare but longer. Then in mid 1990's something happened and cuts became even rarer and seldom lasted more than a few seconds. The exception was when the cable under the High St shorted two phases together.

(*) It was explained that if the cut was long enough for the tank to fill to the brim then the electricity company would consider re-imbursing us for the cost of a suck out by the council's cess pit service vehicle.