Connecting a generator to essencial circuits

[spider]

Hi All,

I have a few questions and would like your opinion and advice on please, recently housed local to us have had a power outage for 30hrs, and this got me thinking (dangerous I know) about using a generator to feed essencial circuits.

The house supply is TN-C-S
Crabtree Starbreaker split load CU

What I was thinking is to install a Gewiss GW66004 switched socket oulet fed from a 10A RCBO on the non RCD side of the CU, (The genny is only 2.2kVa)

The genny would be plugged in using a modified plug at the genny end (neutral & earth joined)

Also I would install an earth electrode using 16mm to the CU earth bar

Operation would be:

1 Isolation and locking off of the main incoming supply at the CU when utility power is lost
2 Isolate MCBs except lighting and sockets (loads disconnected except FCU feeding heating)
3 RCBO to genny socket on and backfeed into board

Whats your thoughts, is it feasable.

Cheers

 

[ajelec10]

Another way to provide interlock between the generator and the main switch is to have (hope fully already installed) lockable isolaters you can then get two padlocks with a trapped key this then makes the two isolators interlocked with a bit of modifaction.

 

[spider]

Well, got the changeover switch from Senate Electrical in Peterborough and its just the job, had a chat to e-on and I just have to give 5 days notice and they will cut the seal, and the same day, reseal at no cost.

Just got to get a few more items in preparation for the big day in the new year.

 

[Davey101]

Interesting thread. I've wondered about the best (and cheapest) way of doing this in a house in the past, as the only backup/genny stuff I have done has been in larger installations. Keep us updated.

 

[wattsup]

You can get a 6kva diesel set pre-wired for auto start for about £1000, the auto transfer switch itself about £400 extra. Care needs taking not to overload the set, so its wise to allow only essential circuits to energise on changeover.
I would always use manual transfer for small sets (under 12kva) unless alterations to existing circuits can be made. B&S have a nice manual switch, 40A max on generator supply, auxillary skt, and warning lights about 200 quid tho

 

[spider]

Just a quick update before the festivities, total expendature to date is £136.00, only things left to get are a couple of 50cm lengths of 25mm meter tails.

I will post up some pics in the new year when you are sick of turkey and any distraction would be welcomed, the rough drawings I have attached show, current set up, proposed and a cable schedule to go with the house file.

Have a great Xmas & new year.

Cheers

 

[spider]

Just checked my small portable generator (2.2kVa) and the body of the machine is not common with the Neutral terminal as mechelec suggested.

I will be maiking up a bespoke lead for this emergency duty anyway, so will connect the nuetral & earth together at the generator plug to allow the RCD protected circuits to operate as normal on the consumer unit.

 

[Guest123]

I will be maiking up a bespoke lead for this emergency duty anyway, so will connect the nuetral & earth together at the generator plug to allow the RCD protected circuits to operate as normal on the consumer unit.

Seems your easiest option.

Just install your earth rod and away to go.

 

[wattsup]

Ditto to above, don't convert generator....nearly always

 

[Frenchsparky]

That is pretty good details about the UK useage with generators however I will give you both USA and France verison of generator useage.

USA side

There are few ways it can be done .,

Manual changeover

Automatic changeover

Localized conneciton

For manual changeover it is most common and cheaper than automatique changeover useally by few hundreds Euros even thousand Euros with larger units.

However the typical North American standby manual units typically use any generator from 7.5Kw to 15 Kw { 12.5 Kw is most common } some are cord set up and some are hardwired units but pretty good percentage of homeowner do have portable gennys they are typically from 3 to 8 Kw size { half of the time they don't work due they never exerized it at all }

For Automatique set up due the current code { regualations } they have to be sized to matched the service size in USA side typically 200 amp service will require 48 Kw generator and IMO that is plain silly and will cause serious issue espcally with diesel units and I know I did check the total load what they normally load it up and they don't go over 50~70 amp the most ditto with 100 amp service which they require 24 Kw genny that is alot more than it need to be used.

It is fine for Hosptail or large industrail useage where they can sized the unit to pick up the whole load

France verison

We do have manual or automatique changeover point switch some are before the CU and some after the CU to size it I useally sized it under the max rating of CU unit.
The reguations is almost simauir to your UK reguataions

Merci,Marc

 

[spider]

Quick Update:

The Transfer switch is now ready after the addition of a multifunction meter which will display, volts, amps. kW and frequency.

I have wrote to EDF Energy seeking permission to install the switch in the external meter cupboard, if this is declined, I have a little bit more work to do, but it will fit local to the CU.

I have a picture for your entertainment

 

[dragon-av]

Nice looking unit and may i say a very tidy office/desk wish mine looked like that. How will you wire the MCB to make sure only the specified circuits get transferred? My uncle has a similar thing done I dont know how its wired it was put in as part or a rewire/upgrade he had done and he had the genny out to run some bits while the board was changed and the spark said he could aire it in for him but i dont know how it was gone and doubt he does i think there is a large SWA running from garage where genny is to the house in addition to the SWA feed to garage.

In fact I have just bee having a google on the subject quite interesting really just been looking at LGP conversions for gen sets (ideal in a fixed install and cheaper to run if its used regularly and easier to change fuel over while genny is running...

found a useful american guide here PM: INSTALLING A BACKUP GENERATOR: MARCH 98

lpg kits here Edge Technology - Benefits of LPG Gas.

Auto changer over regulator TPA - ACR6 Two Cylinder Automatic Changeover - LPG Calor Gas Propane Regulator (TPA01) - Auto Change Over Va

now just need an auto changeover for the power and apart from checking the tanks its fully automated power backup....

This looks ideal Honda EM5500s electric start generator + dual fuel LPG on eBay (end time 29-Jan-10 14:01:15 GMT)

 

[andyh]

Quick Update:

The Transfer switch is now ready after the addition of a multifunction meter which will display, volts, amps. kW and frequency.

I have wrote to EDF Energy seeking permission to install the switch in the external meter cupboard, if this is declined, I have a little bit more work to do, but it will fit local to the CU.

I have a picture for your entertainment

Excellent information on your setup. I'm carrying out a similar setup but am starting from scratch on a new build. I've been researching transfer switches and best manual one seems to be the B&S one. Expensive though! Like the setup you have and wonder if you can tell us how you wired up the switch with the multi meter and what the connections look like inside?

During my research I came across this control panel which is roughly the same price as the B&S but seems to offer much more and has an auto changeover.
Automatic Generator Transfer Switch Controller with Metering

I've emailed the manufacturers to see if this would be suitable in a domestic situation. Anyone have any comments on the above system and whether it could be utilised with normal 25mm meter tails as the mains feed?

 

[spider]

As the use of this project will hopefully be so infrequent that it doesn't warrant an auto starting generator, but that peice of control kit looks really good.

I have written a procedure, prior to use, and in that it lists the breakers to isolate before starting and transfering load to the generator to prevent overloading, the spliting of essencial loads can be manually managed in my case.

I have attached two pics, one showing the rear of the power meter, the other the connection arrangment.

Tip: Don't trust the meter template that comes with the instructions to be accurate grrrr, centre punched through the template, marked out, drilled, only to find the holes were out, luckily the front covers up the mistake.

Connection wise, I have used bootlace ferruls on the cables to make them tidy, neutral uses a straight through DIN rail mounted connection, the live passes through a fused DIN rail mounted connection.

I did have to extend the current transformers connections to allow the lid sufficent slack to be moved out of the way during serviceing at a later date.

The sleeving has a conductive drain wire, hence the use of a pyro copper clip to earth.

Thanks for the links and info, I found loads of stuff on youtube about the connection and use of home generators, was seriously sad, sat infront of the lappy, headphones on listening to some guy in a check shirt talking about his setup

 

[dragon-av]

Thanks for the links and info, I found loads of stuff on youtube about the connection and use of home generators, was seriously sad, sat infront of the lappy, headphones on listening to some guy in a check shirt talking about his setup

Thats me most of the time....Oh to have the money to buy a shell and do it properly...

http://www.smartpowershop.co.uk/UserFiles/File/pdfs/X008_00003.pdf is nice only missing (although easily doable) is the GSM modem to send SMS or call to alertl you gen set is active and running...

I have a client who was thinging of UPS for his security system and has a genny on site (was being used before mains connected and i recon the Auto start unit is cheaper than a UPS) May need a small UPS for change over.

A mate who used to engineer in hotels had cathedral gensets and massive power factor correction capacitor banks they used to kick the genny in regularly to keep the load on the grid down to specified amounts but that used air breakers a bit over kill for a house?

 

[spider]

Excellent information on your setup. I'm carrying out a similar setup but am starting from scratch on a new build. I've been researching transfer switches and best manual one seems to be the B&S one. Expensive though! Like the setup you have and wonder if you can tell us how you wired up the switch with the multi meter and what the connections look like inside?

During my research I came across this control panel which is roughly the same price as the B&S but seems to offer much more and has an auto changeover.
Automatic Generator Transfer Switch Controller with Metering

I've emailed the manufacturers to see if this would be suitable in a domestic situation. Anyone have any comments on the above system and whether it could be utilised with normal 25mm meter tails as the mains feed?

Andy,

Save your money and slot this little baby in

[ame=http://www.youtube.com/watch?v=1j8rQEOf6zE]YouTube - Double pull Double Throw Changeover switch.divx[/ame]