domestic backup generator supply

[donnysparks]

Hi,

I'm looking for some advice on backup generators. I'm doing a new build and the client wants a backup generator for some lighting and power and possibly heating for when there are power cuts in the winter. What would be the best way of doing this? Any advice would be really helpful. 7

Cheers D

 

[Knobhead]

What do you know about the legal and safety implications? Tell us what you plan and we’ll go from there.

 

[donnysparks]

Well to be honest never done a generator before. As far as I know a separate earthing arrangement will be required for the circuits the generator supplies such as an earth spike at the generator and possibly another at the DB and perhaps use of rcbo's. Also it will have to be done through a change over switch.

 

[Engineer54]

Well to be honest never done a generator before. As far as I know a separate earthing arrangement will be required for the circuits the generator supplies such as an earth spike at the generator and possibly another at the DB and perhaps use of rcbo's. Also it will have to be done through a change over switch.

How the hell are you going to achieve that??

 

[donnysparks]

Read the question mate, NEVER DONE A BACKUP GENERATOR BEFORE, LOOKING FOR SOME HELP OR ADVICE!!

 

[Engineer54]

Your best bet is to contact prospective generator manufacturers/suppliers and ask them to give you a scheme you can work too. To be honest i can post you chapter and verse about the DO's and DON'TS, but that's going to take a bit of time explaining things along with the whys to someone that has never worked with generators and controls. Far easier to let the interested parties give you all the information, then if you questions, i'll be more than happy to help....

 

[donnysparks]

Thanks for that mate, can you recommend any good manufacturers/suppliers I could contact. Also just for my own piece of mind, would I be right in saying installing a small essential services board for sockets, lights and heating through a generator transfer switch and using an earth rod for the main earth when the main power is off?

 

[Deleted member 38070]

BST9200M manual change over switch (briggs and stratton) with earth rod. very good has inbuilt 30mA search net for manual hope this helps

 

[Engineer54]

Thanks for that mate, can you recommend any good manufacturers/suppliers I could contact. Also just for my own piece of mind, would I be right in saying installing a small essential services board for sockets, lights and heating through a generator transfer switch and using an earth rod for the main earth when the main power is off?

I'm not that up on the smaller generator set-ups, more used to the 1MVA and up variety, ...lol!!. All you'll be going to be doing, is adding another supply source. Nothing within the installation needs separating as such. There is many things and ways you can use a quality generator supply, load shedding is one that jumps to mind, but a bit OTT for a domestic installation. Size of the unit (KVA) is your major first hurdle, too small and it becomes a waste of money, too big and you chance the engine destroying it's self in a relatively short period of time.

See, already getting complicated, which is why it's better to get as much info from the manf/suppliers. My choice of Gensets in the UK would be Wilsons, but i'm sure there are many more around that specialise in the smaller units etc....Remember, ...you can also have a fully automatic start and change over system. they are not always Manual, can't say i've ever worked with a manual start and change-over!! ..lol!!

 

[Lighthouse Phil]

As E54 has said, you really need to know what size genset to install. My wife also says size is important. :cuss: Too small and you'll work it to death in no time. Too big, it will shake itself to death. Its important to match the genset with the expected load.
You can have them on Auto-start up, monitoring the Mains and starting when it sees the V's drop below a predetemined value. It will also disconnect the mains supply via a contactor so that NO power is sent down the suppliers line. Its been said already, it could get very involved here, give a bit more info and I'm sure you'll get the right answers here

 

[Knobhead]

Read the question mate, NEVER DONE A BACKUP GENERATOR BEFORE, LOOKING FOR SOME HELP OR ADVICE!!

And you think people will help now? As far as I'm concerned you're on your own.

Concider what I said in #2

 

[eollou88]

You can use mems or the generator company this is who we use as our sub contractors, I prefer mems though, have a look on the tinternet.


Sent from my iPad using Tapatalk HD

 

[EastAnglian]

I have a very similar request from a client - I'm not bothered at this stage about the specification for the generator, but reading the notes for the suggested Briggs & Stratton manual change-over switch (see here: Which Generator advice and tips ) shows a local earth electrode permanently connected to the installation. This is obviously a requirement when viewed from the local generator's perspective, but my client's supply is currently TNC-S.

Therefore the question which is upper most in my mind at the moment is do I have to change the means of earthing from TNC-S to TT? If the answer is yes then I will need to revise the installation to meet the RCD requirements for a TT supply.

I realise this is only a part of design exercise which is required, but some guidance on general good practice, nay even compliance with the BGB would be appreciated!

 

[Lighthouse Phil]

Your Genset should have its own earth rod,, as well as linking the Neutral and Earth in the alternator. Your GenSet is Earthed TNCS, or PME.
Make sure that you have a electrical as well as mechanical lock between the 2 contactors. (one contactor for Genset, one contactor for mains Supply) so that in no event can the genset supply the grid.
There should be no need to change your current earthing arrangement to TT.

EDIT:::
Link the frame of the GenSet to Neutral for Earthing in the alternator.

 

[Knobhead]

Don't try this with a site generator, they shouldn't be used for home back up systems.