On Thursday, June 26, 2014 10:43:55 AM UTC+1, wrote:

Hi All,
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

that's huge

and we need to run a small PA system,

couple hundred watts?

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,

2-3kW presumably

small water heater for the sink and basin taps,

?

occasional use of twin hob Baby Belling sytle cooker

typically 3kW with interlocked elements

and George Forman type grill(s).

1-1.5kW?

Even with diversity, I think it's going to be tight!).

Well, if you interlock prioritised loads it wont be hard at all. What I 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 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 only 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 cycles, 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.


Anyways, i've just been having a look at
http://www.screwfix.com/p/xq-lite-20...ght-240v/10988
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?

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