dimming lights

[AnonymousImport]

can anyone tell me why my cieling lights dim
when I use my upstairs taps (9.5kw water heater fitted) I have this wired to a fuse in the main fusebox which was at one time economy heating (storage heaters)


Any help would be greatly appreciated.

PS not using the taps until this can be clarified

 

[AnonymousImport]

Its called voltage drop.
i will try and explain.

Normally your lights are running at 240 volts (little current)when the heating element comes on it too runs at 240 volts but uses a lot of current.

There is not enough voltage present to run both so your lights dim. (as does the voltage to your heater but you would not notice)

to put it another way, you have a pint of water and 4 glasses each gets an equal amount (1/4 of a pint) then some one says no its 5 glasses not four so you do it again and this time each gets 1/5 of a pint, basically not enough to go round, but it is common in winter as electricity consumption goes up.

 

[AnonymousImport]

thanks but is it safe

 

[AnonymousImport]

it is usually safe.

electricity is supposed to be supplied at 230v +/- 10% (207 - 253v) these days (damned EU directives) and our previous standard of 240v +/- 5% (228 - 252v) fits into this as does the european 220v. In most cases our supplies are still pretty much at the top end of the EU range, but where consumption is high, the voltage lower,

This means equipment designed to survive at 240v may not get enough voltage to operate at full power whilst much modern kit is designed for the wider european market where the usual supply voltage is 220v. in usual supply conditions these may run a bit hot shortening it's life.

if you have the right tools and know how you might measure the voltage when the heater is on or the supplier could do it for you. If they are supplying you too low a voltage they may have to uprate your supply, but it is unlikely they will be supplying lower than 207 volts even in really heavy consumption periods