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Isolater Circuit - Heavy Duty Relay

Practical Motorsport Wiring - Club Level

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A little preamble, before I pose the question. I've so far installed a heavy duty relay as the isolater "switch" in 3 rally cars, and to date have had no problems. The unit I use is this :


Recently, on a Facebook thread, doubt has been cast on the long term appropriateness of this item.

My question - is it a viable option? I am using it instead of a "big red key" master switch - basically because it is very easy to fit two (or more) cut-out switches anywhere on the vehicle.

It should be ok for a typical rally car. It says 130a continuos and 300a switching current capable. A 4cyl, low comp turbo motor wont draw massive current during cranking. And most importantly, the main relay wont be doing the "switching" of the starter motor current. (Which is the making and breaking of the high current circuit, which wears contacts the most)

And generally speaking, rally cars dont do that many KMs either. And they will never see anywhere near 130a during regular operation. Also says good for 5x10^5 cycles at 300a. Which is alot more than a rally car will do in a lifetime.

Things like light wieght components are sometimes more desireable than something that will never ever wear out. And using relay instead of multiple isolator switchs, saves on wiring wieght aswell as switch wieght.

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