What would cause a Spur Switch light to go off when the device is turned on?

Question

I have a fused spur switch in my kitchen with a dishwasher attached. Recently the dishwasher stopped turning on, so I removed it from the bay and noticed two things.

• The neon light is quite dim.
• When turning on the dishwasher (which never appears on), the neon light seems completely unlit. I have uploaded a video to youtube demoing this behaviour.

The dishwasher has been working for the last six months without fault so far.

It is a UK 240V (50Hz) wired house, but presumably whatever electronic engineering principals would apply to this circuit generally.

What would cause this?

Answer 1

Assuming the light itself isn't bad, then the combination of a dim light and the dishwasher making it go out sounds like a break in a wire or a corroded connection. A break or corrosion can allow enough current to pass to light the bulb dimly, but when a higher current is called for the resistance of the break or corrosion goes up, causing an apparent total failure.

See https://diy.stackexchange.com/a/27285/82