Low Voltage

[davidjenkins76]

hi, am david jenkins, somebody answered my 1st queries here, thank you.
my other problem is that about our power supply, am just wondering during at night were always experiencing low voltage, is it because there something wrong on our wirings, does it effect our internet connection and last will it be a cause on damaging some electronic gadgets i`ve been using during the power supply corrupted?

 

[Scoby_Beasley]

Your voltage has a tolerance. It should be 230V +10%/-6%. That is 253V down to 216V. Although you are more likely to be running around 240V.

Voltage sensitive equipment is more likely to be damaged with an over current. Having said that, I'm not sure if a low voltage would damage anything, I'd expect it to just not work!

And I wouldn't think it would affect your internet as that is telephone related and runs at very low voltages.

 

[davidjenkins76]

thank you Scoby_Beasley

 

[ricicle]

at night were always experiencing low voltage

That's perfectly normal !

If you mean the voltage is lower than normal, then as long as it is within tolerences then no problems should occur. Your kettle might take ever so slightly longer to boil.......

 

[ericmark]

Old meters did measure amps and based the watts used on the assumption that the volts would be 240 volt so under voltage mean you paid more for your power. Not sure on new meters maybe they measure the volts?

Fan failures was the thing I found dangerous with under voltage. Fan heaters should not be left unattended and should have thermal fuses in so if the fan fails the fuse will blow. But if not at the designed angle i.e. tilted to blow up or down rather than sitting flat then the fuse may rupture too late. I have had one fire due to a fan stopping in a fan heater likely due to excessive volt drop.

Although under voltage may cause mains hum on audio equipment other than the fan heater I know of no danger through under voltage.

I have had low voltage damage air conditioning units. It was rather extreme in Algeria when I worked there the supply was three phase 110 volt which will give 190 volt phase to phase but the Dutch electrician had forgot it was three phase he thought it was split phase so was trying to run 220 volt air conditioning units 30 volts below design voltage even when there was no local volt drop. The pumps could not start and the auto reset device would in the end fail as being reset so many times.

But in a UK domestic house never seen the volt drop low enough to cause problems. In caravans and boats in parks and mariners yes but not in a normal home.

 

[ricicle]

Old meters did measure amps and based the watts used on the assumption that the volts would be 240 volt so under voltage mean you paid more for your power

Had would that work then ?

Less voltage means less amps. Even the 'old meters' would still be seeing less amps, so less power....

 

[winston1]

Old meters did measure amps and based the watts used on the assumption that the volts would be 240 volt so under voltage mean you paid more for your power

Had would that work then ?

Less voltage means less amps. Even the 'old meters' would still be seeing less amps, so less power....

What he said was rubbish. Old meters and new meters have always measured true power. There was a voltage and current coil and power factor was taken into account as well so it always read true power.

The so called energy monitors don't however. They just measure current and assume a fixed voltage and unity power factor, neither of which ever happen.

 

[securespark]

Lots of PSU's for lappys etc run happily from 100V upwards.

 

[SimonH2]

As ericmark hints at, the main issue is motor driven equipment. Low voltage tends to make the most common motor types run slower (with increased slip). This results in higher power losses in the motor at the same time as it's cooling fan is moving less air.
In extreme cases, and depending on the nature of the load, the motor might not have enough torque to start - what happens then depends on whether it has any effective protection (some will just burn out).

At work we get higher voltages at night - less load on the distribution system, less volt drops, higher terminal voltage for end users.
But at a previous job I recall a discussion with one of the guys we had working there. He live in a small group of houses in the middle of nowhere = one the end of a long local supply branch. Several houses had night storage heaters which had a profound impact on supply voltage when they turned on and off.