I Have 10 400w Lights Can I Use 30a unused E Cooker supply


Postby WeeGogs » Mon May 17, 2010 11:00 am

I Have 10 x 400w (4000w ) Lights with an igniter and ballast for my driveway Can I Use 45a unused Electric Cooker supply from my house and junction them all up or is there a better way to power these without having to use different sockets on different rings etc.
if i switch them on all at once there will be a high amount of draw/surge during power up.
can any one explain the best way to do this.
WeeGogs
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Postby ericmark » Tue May 18, 2010 12:07 am

Much will depend on how switched. Discharge lights have a high inrush on switch on and if you switched them all on together likely it would blow a 32A supply.
Assuming correctly fitted then 10 lamps will be lighting rather a large area when I was lighting a factory 70W was norm at 10 foot up and the 400W lamps were mounted on top of the silos and I had complaints from local police that they dazzled drivers on a roundabout 1/2 a mile away. So one does have to be very careful and of course any lamp over 150W requires planning permission.
I would assume you are living in some country estate with a couple of mile driveway to need so much light or it doubles as a foot ball ground and so really it needs full plans drawing up to be submitted to local authority and I would suggest this is not a DIY job and you would be better getting some one in to advise. I found many supplies offered a FOC service for lighting projects which are so large.
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Postby WeeGogs » Tue May 18, 2010 12:54 pm

Thanks i will get professional help anyway, i just wanted an idea on how the guys could power them. my driveway is 1.7 miles long (in scotland) 75 metres wide with another persons private property either side, i have a 7 foot wire fence to keep my deer in with 7 foot electric gates.
the poachers come through the fence at night and stalk and kill the deer, i was hoping this would be enough light to frighten them off.
but thanks for your help eric, probably cost me a fortune to get a cable laid but i need the security.
and the brighter the better.
and THANKS.
WeeGogs
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Joined: Mon May 17, 2010 10:26 am


Postby ericmark » Tue May 18, 2010 8:54 pm

Doing a quick calculation that would need at least 160mm² cable in fact even with that looking at around 12 volt volt-drop over that run. Dropping the size to 150w sodium would reduce cable size to around the 25mm² which is more reasonable.

I was surprised how much light you get from 70W units. I have a metal halide 70W which is brighter than my neighbours 500W quartz halogen this is in some way caused because the fitting is larger and gives a better spread.

You may wish to consider the colour of the light. I am told that the orange light from sodium lights is closer to the best the human eye can see so humans can see further with sodium lights than with white lights of same power. However same is not true for cameras and also they do not reflect well so high visibility jackets don't work too well.

Using higher voltage would reduce volt drop but by time you include price of transformers likely not too much of a saving.

Discharge lights don't like being switched too often so movement sensors not really an option.

There is special cable used for street lamps it is a co-axial design and likely cheaper than steel wire armour also there may be tapping in some lamps to allow for volt drop so you may find there is a method to reduce costs if you go to someone who is conversant with street lighting.

All best with your project.
ericmark
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Joined: Fri Oct 02, 2009 8:49 pm
Location: Mold, North Wales.


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