500w Outside light

[dunny]

I am fitting an outside light (500w halogen) that will have a switch in the kitchen to control it. I was intending to use the JB method to wire it up and instead of using 1.0mm lighting cable I am intending to use 1.5mm (just from the JB to the light not as the switch cable). I have 6 x 60w lights on this circuit, 1 350w outside halogen and a couple of switch operated wall lights. The fuse box (RCD and only 3 years old) has a what I believe to be a 6A fuse in it.

Is this too much for this circuit? Do I need a different fuse?

 

[nstreet]

I hope that nobody lives opposite your 500W halogen, these things are a nuisance in residential areas. 500w is not needed to light a bit of garden or driveway. We live opposite one and its like Blackpool bl00dy illuminations, especially in the winter. Frequently get woken up during the night because the room is lit up, thinking its morning, only to find its 2.00am

 

[dunny]

Its in the back garden and its switch operated not on PIR.

BTW - I had some advice from qualified electrician (part P qualified) and he said that this should be fine but I ask as some other posts on here suggest otherwise?

 

[stevesey]

Can't help but agree with nstreet - whatever you do make sure it is tilted well down so the beam cutoff falls within your garden (and not the house behinds lounge). Although this normally means you can't get the PIR to cover a decent range as it won't tilt back up far enough (basic design flaw!)

I replaced our 500W yesterday with a 150W - went out into the garden last night, plenty of light, could have easily sat and read a book.

 

[dunny]

Take your point but nobody behind my house so no problem. As I said not PIR in any case so will only be on for short periods mainly e.g. emptying bins etc

Still would lke an answer from someone if poss. Wheres Damocles, Ban-All-Sheds, FWL_Engineer etc, always a fountain of knowledge?

 

[ban-all-sheds]

I am fitting an outside light (500w halogen) that will have a switch in the kitchen to control it. I was intending to use the JB method to wire it up and instead of using 1.0mm lighting cable I am intending to use 1.5mm (just from the JB to the light not as the switch cable). I have 6 x 60w lights on this circuit, 1 350w outside halogen and a couple of switch operated wall lights. The fuse box (RCD and only 3 years old) has a what I believe to be a 6A fuse in it.

1210W + the couple of wall lights, i.e. 1310 - 1410W? 5.7 - 6.1A?

Also, in terms of design, lighting outlets should be assumed to be a load of at least 100W each - if your 6 x 60 are 6 luminaires that happen to have 60W lamps in, they should be calculated at 600W, not 360.

The circuit is safe, and if in your judgement you'll never have everything on at once, perfectly OK. But it might be better to have this 500W light on a ring main spur...

 

[plugwash]

also especially if this lot is halogen and you may have trouble restoring power after a trip without making sure everythings off first

i know that turning on 2x500W holgen floodlights at once will frequentry trip a B6 with the inrush currents.

 

[dunny]

Thanks, only 2 halogens the rest are basically normal bayonets at 60w. There are 2 outside lights down the side of the house but they are still only 60w. Unlikely to have all the lights on at once as they are kitchen, utility, WC conservatory (wall lights) and the 2 halogens (1 @350w , 1 @ 500w). Still got time to spur off the ring main in the kitchen but that has 4 fused spurs on it (cooker ignition, hood, dishwasher and fridge). Is spurring off for the wall light pushing it? I could spur off another circuit if necessary??

Cheers

 

[plugwash]

if you can i'd say put the two big halogens (the 350W and the 500) on a new C6 breaker.

 

[dunny]

Cant do that but I can spur off a ring main if it was absolutely necessary. As long as all is well, ie not dangerous, which the general concensus suggests is fine, I will probably leave it.

Cheers for all the help this forum gives, as I have said before this is a very active and knowledgeable place to visit..

 

[securespark]

Would advise against C breakers in domestic...only really required on banks of pf corrected flu's like shops & offices have...

 

[plugwash]

at least from what LS tells me a pair of 500W halogens will take out a B6 at switch on

now theese may not be switched together but i'd still prefer to have the headroom for thier combined inrush at reenergisation after a power failure or whatever.

i agree the larger sizes of type C require great care for domestic use but there is no real problem with the C6.

 

[ban-all-sheds]

1) Don't use an MCB at all - see if you can get a DIN rail fuseholder for your CU.

2) Put them on a B10 feeding an FCU with a 5A fuse in it?

 

[mapj1]

A quick flick with the ohm-meter will tell you the cold resistance of a Q/H lamp is about 1/12 to 1/15 of the resistance you would expect from the wattage (so the current at switch on is higher by the same factor) A single 500W QH would be ~2A (accepting round numbers between friends and all that) once warm, so we can expect perhaps 20 to 25A inrush when cold. A B6 near the upper limit of Imag=5 times Ithermal will hold reliably on switch-on, but a frisky one, near the lower limit, of twice, almost certainly will suffer nuisance tripping.
If on a lighting circuit, use a C6 or a B10, or if you might ever want to isolate it for repairs or whatever, and still have the indoor house lights on, consider a 13A switched-fused spur off the power circuit as a neater alternative.

 

[dunny]

Fascinating stuff. I realise how little I know!!