In message , "Dave Plowman (News)"
writes
In article ,
Steve Yerbury wrote:
The risk is low, but it is still a risk. I believe mobiles should
not be used when dispensing petrol.

Please explain how the sparks from a starter motor commutator are
therefore safe?

I did not say they were

Better push your car off the forecourt, then...

Why?

Petrol vapour is heavier than air.
agreed
Nozzle in tank - phone to ear. Starter
motor is usually near the bottom of the engine - so within about a foot or
so of the ground. Near maximum petrol vapour surrounding it.

Disagree. The concentration of petrol will be around the nozzle/filler.
Unless of course you are in a confined space and there is no
ventilation.

Now starter
motors aren't rated for continuous use so don't have ventilation. So I
suppose any explosion *might* be contained within it. But old cars with
dynamos certainly did have the commutator exposed to the surrounding air -
they have a fan pushing it past it, and they sparked too.

Of course RF (microwave) energy can cause a fire. Everyone with a
microwave oven knows you can cook with them. But they produce hundreds of
watts of energy. A mobile phone about a maximum of 1 watt - and only for a
very short time. And of course they can produce that maximum RF when
simply 'talking' to their nearest base station while not in actual use.

RF is a red herring.

I've yet to see a plausible explanation about why a mobile phone can be
left on but not used close to a petrol pump.


The guidance from the HSE says it must be turned off.

The risk is small, but it is still a risk.

--
Gerbil