relays

I have to wire in loads of accessories to my series 2 Searle ambulance control unit, ie beacons ,2 tones ,bell,spot and fog lights, rear cabin heaters ect. I want them all to turn off with the ignition switch.
They will all be wired though relays but I wondered if they could all have their supplies fed from a relay off the ignition switch as I do not think the switch is strong enough. Would a relay last being switched on for long periods. Or is there a better way.

you might be best off fitting a couple of these !

A relay is switch that is switched by something. The ign switch could switch on/off hundreds of relays.

The power to work all the additional stuff could come straight from the battery.

Having a relay switched on all the time should not be a problem provided you do not run too much current through it. You might consider using the ignition switch to power one relay which then sends current to activate other relays thus splitting up the current demand. Having said that I see lots of 12v relays rated at 40 amps and I doubt all your accessories would draw 40 amps.

Typical automotive relay will draw a couple of hundred milliamps.

all the extra electrical items are fitted with relays so I will fit a relay operated from the ignition switch to operate all these extras. this way I will not leave things on by mistake. May also run heater wipers and washers through this as well to keep the area around ignition switch uncluttered

minecab said:

all the extra electrical items are fitted with relays so I will fit a relay operated from the ignition switch to operate all these extras. this way I will not leave things on by mistake. May also run heater wipers and washers through this as well to keep the area around ignition switch uncluttered

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Make a crib sheet, so when something doesn't work you can refer to it ...

I used pdf writer to edit an original landrover drawing , not much still original . carry a laminated copy in the landrover.

Agree with the above, link a "master" relay to the ign then use this supply the others. This is not quite as simple as that as there may be some circuits where the switch is on the power side and some on the earth side so you may end up separating the switched and earthed. You may be able to use a double pole relay if this becomes an issue. For example, for reasons known only the themselves the makers of my intermmitent wiper box made it earth to wipe but live to wash-wipe, arrrgh. It also pays to think about where to put the realy, so that the power/current wiring is shorter and the control wiring longer. When I got mine the PO had wired in a lot of relays but put then on the dash with thick cables everywhere. I moved them to be close to the battery and lights and ran thin cables into the cab. I also ran one thick supply cable to the rear, then powered a number of things off that.

my relays for head dip fog spot warning bell and two tones are all on radiator panel and control relay behind switch panel near steering wheel along with aux fuse box