mains to generator

[james king]

hi all

now i have worked in comercial for a number of years also done a lot of domestic with my boss ect.

now i have been asked to wire up a main power/ generator switch in order to provide the property in emergancy cases..

i have been provided with me switch and has the following terminals

MAINS GENERATOR
L1 L2 L3 N L1 L2 L3 N

now the question i have is

how to wire the main supply

if you wire the incoming supply in to this switch and then from the main side to the CU........

when the switch is turned to the gen side it would then send 415V back up to the supply and back through the DNO meter

any one ever done one of these b4?

as i know on here some will say if your not competent dont do it lalala but i know i am just need help on this matter as this is a help forum

thanks

 

[Engineer54]

You need a change over switch, either manual, or automatic. It will separate the 2 supplies, so that only one can be the supply to the installation at any one time!! It Must be 4 pole too, never have a common neutral between mains and generator!!

 

[james king]

the switch had been tailor made... the owner knows a man who makes them for a living.... as far as i am aware the connections are mains L1 L2 L3 N then the switch then gen L1 L2 L3 N

thats all there is inside of the metal clad box,,,,,,,

as for this switch how would i wire it from that? surely 3 connections should be made

incoming.... mains.... then generator

not just mains and generator

 

[james king]

there is a link between N on both sides

 

[telectrix]

if the genny is electric starter, you could make it start up when the power fails. as engineer54 states, your changeover device must select mains or genny , only one at any one time.

 

[james king]

yes i understand tht mate... what in confused about is wiring of it... as there are only

mains in

L1 L2 L3 N

the gen side goes to the socket on the side of the box

so there for how will i wire it not to go back throught the meter

ill try to draw a pic and explain

 

[james king]

or do u wire taild from the gen side in to the blocks aswell so both sides would be feed depending on wat ever side u want to switch

 

[james king]

like tht ???

 

[Engineer54]

A change over switch has 3 set's of connections DNO Mains, Generator, Load (consumer unit in your case) Only one of the main supplies will connect to the load in either position.

 

[Graeme Harrold]

Neither of those drawings look like they are switching between supplies. If you loose grid power, you must disconnect that supply before the gen supply is connected. Your switch should have two inputs (Mains and gen) with one output....

 

[Engineer54]

the switch had been tailor made... the owner knows a man who makes them for a living.... as far as i am aware the connections are mains L1 L2 L3 N then the switch then gen L1 L2 L3 N

thats all there is inside of the metal clad box,,,,,,,

as for this switch how would i wire it from that? surely 3 connections should be made

incoming.... mains.... then generator

not just mains and generator

If i were you, get this guy who makes these tailor made switches, to explain to you how to wire this switch up maintaining isolation between DNO and Gen set?? Because i don't see how it can!! And linking the neutral out between the 2 supplies is a No No!! 4 Pole all the way, or you'll be getting stray currents all over the place, and god help you if there are any RCDs in either of the 2 systems...lol!!!

 

[mogga]

change over switch both mccbs with link across load terminals incommer from both grid and genny to bottom of mccbs controlled by loss of power change over switching realay,
Iv only ever connected these up as they came as part of inbuilt pannel board
Any Iv seen with no fixed genny have had Castel switches fitted to prevent premeture change over and double feds ie from both genny and mains Dont know much about internals

 

[james king]

think i will give him a call... rcd and rcbos every were

 

[james king]

thts y i got confused lol because if it only had to cable teminals then there would never be a seprate supply even when u turn it on it would still run through the DNO supply if u get what i mean

 

[Knobhead]

The generator is shown going to the wrong side of the switch. As you’ve drawn it if you switch to the generator you will back feed in to the DNO supply. The DNO’s have enough problems with people connecting generators in to the system, without you adding to it. You cannot interconnect the neutral. As for it being a specially made switch, a standard off the shelf 4 pole on load change over switch would have done.

Many people on this board are fond of saying get someone that knows what their doing before you kill someone, in this case it’s a real possibility.

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