Shower causes light to dim - expected?

On Tue, 27 Mar 2007 22:05:51 GMT, "Bramble-Stick" mused:

It can be normal, and usually is.

It's not desirable and may point to a fault in your wiring or your supply.

Owain

Chances are it is probably normal. Showers place a very high current load on the supply, which will in effect try to pull the voltage down a bit. The more resistance there is in the wires supplying your property, the more noticeable the voltage drop. Ordinary filament bulbs tend to show up even quite small voltages changes as a change in brightness - most noticeable when it is a big load that switched on or off.

(with our relatively "floppy" supply via overhead lines, even a 3kW kettle will dim the lights a little)

and lights on a dimmer are evn more sensitive - you don't just get a lower voltage but for a shorter duty cycle as well.