Fusing of LED floodlights

[cpvh]

Hi All,

I am just looking at buying a floodlight and was having a look at the LED m odels now on offer (it's to be used at a camp where the energy budget is LO W (45A MCB on the main supply cable and we need to run a small PA system, h ouse lighting for a Marquee (3 x twin tube flourescents at 110W per luminai re is what i'm thinking), hopefully a (this) flood for the "stage" an urn f or tea and coffee, small water heater for the sink and basin taps, occasion al use of twin hob Baby Belling sytle cooker and George Forman type grill(s ). Even with diversity, I think it's going to be tight!).

Anyways, i've just been having a look at

Which is listed as a 20W device, but the Screwfix* details suggest fusing i t at 16A. My OHMS,s law is a little rusty, but these two figures seem inco mpatible to me (it is a 240V device).

Do these things have a huge inrush current? or are Screwfix talking nonsen se?

TIA

Chris

*I'd much rather have gone to the local Wholesale Fittings,but they seem to have died, I don't know if Screwfix having arrived on the trading estate a couple of years ago was the cause of this. Mind you, having had a look at their website, unless they are doing very nicely with traditional business from their account customers, I can't see them lasting much longer at all. But perhaps they don't want business from the likes of me.

[meow2222]

models now on offer (it's to be used at a camp where the energy budget is LOW (45A MCB on the main supply cable

that's huge

couple hundred watts?

naire is what i'm thinking), hopefully a (this) flood for the "stage" an ur n for tea and coffee,

2-3kW presumably

?

typically 3kW with interlocked elements

1-1.5kW?

Well, if you interlock prioritised loads it wont be hard at all. What I mea n is decide on a list of load priorities, and automatically shed lower prio rity loads when enough power isnt there to run them. Its possible to run an entire flat on a 5A feed that way, albeit with compromises. DAMHIK.

Its best done automatically with some electronics, but it is also possbile to just do it manually. Write the current consumption on each plug, and onl y plug in upto 45A at any one time.

There are other tricks too, such as switching 2 water heaters to half power when current budget runs out. Feed each via a diode so one gets +ve half c ycles, the other -ve.

If the sink heater is just 3kW those only add upto 10.5kW anyway, which is well within the abilities of a 45A feed.

it at 16A. My OHMS,s law is a little rusty, but these two figures seem in compatible to me (it is a 240V device).

20w is 1/12th of an amp, and the usual available feeds will be fused at 5A, 10A and 13A, so a 16A fuse does seem a little weird.

NT

[Martin Brown]

Certainly enough to support ~10kW continuous load and briefly higher peaks.

Probably less unless it is disco night when they always seem to wind the wick up until it hits the end stop and clipping ensues.

Probably also 2-3kW although you can get slower highly insulated ones that make a volume of warm water and hold it at temperature. This works well until someone runs the tap continuously to get it nice and hot!

We have on in our downstairs VH kitchen.

Microwave or combo oven probably more useful.

Basically just ensure that the ovens and the hot water are never on together and you should have enough supply margin. Have a plan or detailed instructions on what to do if the circuit does trip.

(as sure as eggs are eggs someone will bring in extra kettles for a big event and just plug them in without even thinking about it)

You can't trust end users to do this! I have caught our church Sunday afternoon tea ladies with two 3kW kettles plugged into a fully wound up four way extension cable running flat out. They melted its predecessor.

I now insist that all VH extension cables have thermal cutouts.

Actually this might be an application of the OWL current monitor alarm feature which we have set on our VH so that at 90% of nominal rated load it sounds a warning. The thing is mainly there to make sure people don't leave it with the expensive immersion heater or fan heaters on.

That *is* cunning.

Have a look at Thomann in case they have something more suitable for your needs (we actually have the previous generation of these).

More expensive than a plain vanilla white one but you have the option of colour control and built in sound to light. Minor irritation is it will come with European mains plug. Their white ones are overpriced.

[Nick]

I am just looking at buying a floodlight and was having a look at the LED models now on offer (it's to be used at a camp where the energy budget is LOW (45A MCB on the main supply cable and we need to run a small PA system, house lighting for a Marquee (3 x twin tube flourescents at 110W per luminaire is what i'm thinking), hopefully a (this) flood for the "stage" an urn for tea and coffee, small water heater for the sink and basin taps, occasional use of twin hob Baby Belling sytle cooker and George Forman type grill(s). Even with diversity, I think it's going to be tight!).

Anyways, i've just been having a look at

Which is listed as a 20W device, but the Screwfix* details suggest fusing it at 16A. My OHMS,s law is a little rusty, but these two figures seem incompatible to me (it is a 240V device).

Do these things have a huge inrush current? or are Screwfix talking nonsense?

TIA

Chris

Screwfix page says MAX fusing 16A. I recently installed a 50W led floodlight. That works quite happily from a switched fused spur (fcu) with a 1A fuse. FWIW, the 50W floodlight looks very similar to the Screwfix 20W item. From ebay the 50W cost less inc. p+p than the one you are looking at. HTH Nick.

[cpvh]

LED models now on offer (it's to be used at a camp where the energy budget is LOW (45A MCB on the main supply cable

uminaire is what i'm thinking), hopefully a (this) flood for the "stage" an urn for tea and coffee,

mean is decide on a list of load priorities, and automatically shed lower priority loads when enough power isnt there to run them. Its possible to ru n an entire flat on a 5A feed that way, albeit with compromises. DAMHIK.

ile to just do it manually. Write the current consumption on each plug, and only plug in upto 45A at any one time.

ower when current budget runs out. Feed each via a diode so one gets +ve ha lf cycles, the other -ve.

is well within the abilities of a 45A feed.

ing it at 16A. My OHMS,s law is a little rusty, but these two figures seem incompatible to me (it is a 240V device).

5A, 10A and 13A, so a 16A fuse does seem a little weird.

Cheers for that guys. I had forgotten the Microwave.... and the Fridge Fre ezer....and the Freezer. Oh, and the large screen TV. There are a couple o f kettles on site, but i'd already warned "catering" that they would probab ly put everything in darkness if they turn them on.

This Site is fed by an underground cable which was protected by an 80 Amp F use which always coped with everything we threw at it, but a qualified spar ks has recently (quite correctly) changed this for a 45 Amp (I think that w as the figure, it was round there) MCB as that is all the underground cable is rated for.

I will have a look at the Stage lights, but a small white flood is probably enough and I've blown the electrics budget on the flourescents.

[Andrew Gabriel]

There seem to be a glut of these around - CPC also sell them.

I bought one, and was disappointed with the light output. The 20W one was noticably less light output than a 17W one from CPC (sold as a worklamp), and noticably lower colour rendering. I think they are using cheap lower efficiency power LED modules.

The case is nicely made. I removed and chucked the LED and driver, and bought 4 x 7W LED modules from Rapid and built a power supply for them. Can't quite run them at 28W (case was only designed for 20W).

[Dave Liquorice]

Yes, and they aren't all created equal. I've got a 10 W one (from Amazon I think). The bracket pivot screws are plated steel and where showing signs of rust within 24 hrs of being outside... Some say they have stainless screws but that *may* only be refering to the ones holding the front cover on. Caveat emptor.

[Dave Liquorice]

Not going to happen, most people are so used to just plugging anything in anywhere and it working they get very confused if the circuit trips. Was in the Dr's Surgery a while back and the power tripped, came back then tripped again, rinse an repeat a few times. Turns out the gas heating had packed in so they had half a dozen electric heaters on...

Or take the example of the urn and kettle (ordinary not rapid boil) to provide tea and coffee on outside broadcasts. The urn takes to long first thing, even with a minimal amount of water in it. So the kettle and urn are used at the same time, this is fine on a 16 A feed from the generator but occasionally the feed is a 13 A plugtop. That

13 A fuse lasts about 5 mins if that. The number of my supposedly "technical" colleagues who just can't understand this is rather depressing.

[ARW]

I am just looking at buying a floodlight and was having a look at the LED models now on offer (it's to be used at a camp where the energy budget is LOW (45A MCB on the main supply cable and we need to run a small PA system, house lighting for a Marquee (3 x twin tube flourescents at 110W per luminaire is what i'm thinking), hopefully a (this) flood for the "stage" an urn for tea and coffee, small water heater for the sink and basin taps, occasional use of twin hob Baby Belling sytle cooker and George Forman type grill(s). Even with diversity, I think it's going to be tight!).

Anyways, i've just been having a look at

Which is listed as a 20W device, but the Screwfix* details suggest fusing it at 16A.

It says "max fusing 16A"

[meow2222]

at the LED models now on offer (it's to be used at a camp where the energy budget is LOW (45A MCB on the main supply cable

0W per luminaire is what i'm thinking), hopefully a (this) flood for the "s tage" an urn for tea and coffee,

at I mean is decide on a list of load priorities, and automatically shed lo wer priority loads when enough power isnt there to run them. Its possible t o run an entire flat on a 5A feed that way, albeit with compromises. DAMHIK .

ossbile to just do it manually. Write the current consumption on each plug, and only plug in upto 45A at any one time.

lf power when current budget runs out. Feed each via a diode so one gets +v e half cycles, the other -ve.

hich is well within the abilities of a 45A feed.

fusing it at 16A. My OHMS,s law is a little rusty, but these two figures seem incompatible to me (it is a 240V device).

d at 5A, 10A and 13A, so a 16A fuse does seem a little weird.

1.5kW briefly enough to pretty much ignore.

trivial

that they would probably put everything in darkness if they turn them on.

Fuse which always coped with everything we threw at it, but a qualified sp arks has recently (quite correctly) changed this for a 45 Amp (I think that was the figure, it was round there) MCB as that is all the underground cab le is rated for.

Maybe put a D type MCB on instead. A 45A cable will deliver far above 45A f or a while quite happily.

If you want a permanent excess load, I'd probably make/use a load shedder, but it doesnt sound like youi're going to have any problems - unless someon e puts everything AND the kettles on.

NT

[meow2222]

It depends on the situation. If the person that trips the feed is suitably punished they learn. I dont mean by sitting on the naughty step, but by the results of their actions. It works in the eastern bloc with flats on 8A fe eds, overload it and you're inconvenienced.

Putting a number on each plug makes it elementary. But if you're dealing wi th employees they too often couldnt care.

NT

[Andrew Gabriel]

There was a larger scale one in Luton some years back. Major gas main failure cut off gas to a neighbourhood. Gas company delivered electric heaters to all the houses. An hour later, substation transformer burned out (ISTR it exploded into flames).

[cpvh]

Thanks for all the replies guys. It has turned into an interesting and ent ertaining thread as is usual round here. I think I will go with a conventi onal 300W Flood which is what I've used in the past. If it turns out to be the last straw, i'll just turn it off.

The professional sparks will be on site, so if it all goes pear shaped he m ay be able to do some proessional sparky magic with a type D (if that's not what he's used already), or something else.

Chris

[Tim Watts]

I can be pretty sure he will not have a type D - the Zs (loop impedance) requirements are very hard to meet - you pretty much need a transformer nearby and your 600A distribution panel in the next room!

Type C is about as far as you can usefully go outside of a commercial building with big heavy local distribution cables.

[cpvh]

[Johny B Good]

It's worth considering that a 300W linear halogen lamp will have a turn on surge that equates very closely to the current draw of a 3KW electric kettle. Whilst a 20 to 50 watt LED lamp might create a switch on surge, I rather suspect it won't be quite the magnitude of a 300W linear halogen lamp.

[Tim Watts]

I very much doubt the LED +PSU has any noticeable power on surge, unless it's PSU is large magnetic (50Hz) transformer. Don't think there's too much to worry about :)

[meow2222]

ntertaining thread as is usual round here. I think I will go with a conven tional 300W Flood which is what I've used in the past. If it turns out to be the last straw, i'll just turn it off.

may be able to do some proessional sparky magic with a type D (if that's n ot what he's used already), or something else.

I can only suggest that that's not a good choice now for outdoor lighting

NT

[meow2222]

Both CR and smpsu PSUs do have a switch on current surge, but the i squared t is tiny compared to a 300w filament lamp.

NT

[Andrew Gabriel]

Worse than that - initial current draw is typically 17x running current, which would be a 5.1kW electric kettle ;-)

It will be much shorter, and and probably somewhat lower depending on the quality of the PSU.