Switching 12kW?

[mk1rob]

Hi!

Don't know if anyone can help? Im currently doing a part P upgrade on a customers house. He had an old rewirable fuse board that had a 63A switch fuse off it that feeds his tennis court lights. Its wired from the switch fuse to an outside JB in 16mm 3core SWA then 2.5 SWA after that to the lights. There are 12 x 1000W flood lights. They used to switch the lights on and off using the switch fuse isolator!

I guess ill need some sort of contactor to switch that sort of load? Not had a lot of experience with contactors as mainly do domestic work.

Would appreciate any advise on how to do it properly.

Thanks!

 

[Andy™]

part P upgrade... thats a new one.

 

[Manator]

You are correct, switching that much of a loading can only "really" be done safely by the use of contactors, in fact on some commercial installs contactors are used to swith even smaller loads.

Just read the post again, that sort of loading can be switched by the 63 amp fused switch.

 

[benji]

think i would fit 2 contactors 6 lights on each, switch each contactor seperately with a bit of time delay

 

[alpha spark]

Pass the swa through the contactor use top side as supply and bottom side as load wire a seperate circuit labelled contactor control neutral to a2 live to a 1 gang switch common and from l1 from switch to a1 that cct can be wired in 1.5 dependant on length of run and on a 6 amp mcb easiest way I can suggest

As benji says depends on where the switch fuse is if it's at the mains can't see a way of doing that without running another supply as he says it goes to a joint box where is this joint box

 

[mk1rob]

As benji says depends on where the switch fuse is if it's at the mains can't see a way of doing that without running another supply as he says it goes to a joint box where is this joint box

Thanks for the replies! The switch fuse is at the mains. Ive taken it out for the time being so just got the SWA poking out the wall at the minute. The JB is a waterproof enclosure on the edge of the tennis court. Was hoping to just take a supply from the mains to a switch, switch to a contractor and out to the JB/lights. Is it not that simple? Not sure what contractor i need either :C

 

[Sharpend]

Then he'll come and fit it for you and 5% will go to Admin too.

 

[androidlee]

i'd use a db switch disconnector in enclosure. much more tactile and cheaper than contactor arrangement

 

[steptoe]

but nowhere near as good.

 

[Jono Pashley]

presume he means something along the lines of this? Buy Schneider Switch Disconnector, Isobar 4, Type A, 125A, 230/240V AC, DP - MGI1252

 

[steptoe]

presume he means something along the lines of this? Buy Schneider Switch Disconnector, Isobar 4, Type A, 125A, 230/240V AC, DP - MGI1252

and if you are careful when you put the bat-strap around it to screw it back with you can get the holes to line up with the terminals.

 

[Jono Pashley]

Where's the db bit then ?Schneider - oooohhhhh me and SW will have to disagree :slap

Where is the snake?

i went along the lines of him refering to db as distribution board, so i linked a Switch Disconnector from a DB, not how id do it but not me doing it so no carey.

sure ive seen SW wandering around in a Schneider Electric Ultimate Installer T-Shirt :slap

Steps:

Id laugh but ive seen it done...

Note: the little plastic dispenser for the ARB looks much better than the cardboard carp i seem to get it in

 

[lkayelectrical]

Ummm 12kw on a 2.5mm2?

 

[Badger]

Ummm 12kw on a 2.5mm2?

might start getting a bit warm :slap

 

[ProDave]

Ummm 12kw on a 2.5mm2?

I read it as splitting into 12 runs of 2.5mm, each one feeding a 1KW floodlight, so no problem with cable overload, only about 4 Amps per cable.

BUT their might be an issue with fault protection. Could there be a case for individual MCB's in the junction box where it splits into the 12 cables?

 

[apprentice87]

Hi All,

First off i would definitely use a contactor, anything else is just cowboy land, secondly, I agree with ProDave, at the point where it all splits down into 2.5mm you will have to subdivide the circuits in such a way that you can incorporate OCPD's with a max rating suited to protecting 2.5mm, so i suppose about 20A ones, so say four lights per MCB, and finally, what happens when some one takes a shower at the same time as all these lights are on?? Bye Bye cutout fuse!!!

john

 

[Ash]

isn't there a regulation not allowing you to downsize a cable in a circuit other than tiny distances to appliances (e.g. pendants) without fusing?

 

[hxsarge]

is there an option to put a new db outside/in a cabinet ,on the end of the 16mm and switch it from there with a contactor?

 

[SPECIAL LOCATION]

isn't there a regulation not allowing you to downsize a cable in a circuit other than tiny distances to appliances (e.g. pendants) without fusing?

Pendant is also limited by the possible connected load aspect..

but the other you are thinking of...

is I guess....

433.2.2 (ii) for overload protection

&

434.2.1 for fault protection



but a 2.5mm SWA protected by a ... (what is the actual rating of the protective device used???)

I think we know the switch can isolate 63A safely?

Anyhow...

what would happen with a L-E fault on the SWA...

Fuse trip or cable melt?

:|

 

[androidlee]

not making any sense that SL. in english