Storage heater wired wrong?

[justin1972]

My storage heater has decided to give up so thought I'd check the obvious before calling anyone out next week.

On checking the wall socket I found the Live (brown) from heater wired to L2 and Neutral (blue) wired to N2 as expected. However the supply cable is wired Live (red) to N1 and Neutral (black) to L1. Should the supply cable not be wired the other way round? (I'll have to wait until tonight to check if the red is actually live as it's supposed to be as it's on the economy 7 tariff and so no power is going through the cable at the moment)

The only other thing running on the economy 7 for comparison is the hot water tank and that supply cable is wired as I would have expected ... live to L1 neutral to N1.

The heater was installed when the place was built 20 years ago and has worked all that time so I'm intrigued. Would it normally work if wired the wrong way round and would this account for the Live(red) cable having blackened!!

Many thanks all for you help and Happy New Year

 

[flameport]

The supply should be the other way round, assuming of course that the red is line and black is neutral - if not, there are more problems elsewhere.

A storage heater will still work even with reversed polarity, however it means the elements are always live and the neutral is switched.
Incorrect polarity will not cause a cable to blacken. That is due to a loose terminal or old/faulty switch.

If the heater has suddenly stopped working and power is still being supplied to the heater, it is either the thermostat or cutout, both of which can easily be replaced (or some cutouts can be reset).
If it has gradually been getting worse, as in not heating up as much each time, or only one end gets hot, then the elements have failed and will need to be replaced.

 

[sparkwright]

A loose connection causing burning could have knackered the switch, so check there's continuity running through both the live and neutral of the switch. Also check there's no continuity through the switch when it's in the off position. To do a continuity check like this you must ensure the power is completely turned off.

Also check the fuse or MCB for the circuit is ok.

All these are basic checks before seeing if there's anything wrong with the actual heater.

 

[justin1972]

Cheers for the quick replies. I'll check the supply tonight when the economy 7 hours kick in. Hopefully the cable was installed properly by the builders and it's just the eejit who installed the heater who got it wrong.

I've also found a socket in the bedroom that I've never used as I don't have a storage heater in there and that is wired from the supply wrong as well ... jeez. I shall use that switch in place of the slightly blackened one and keep my fingers crossed tonight !

I can normally hear the hot water heating up if I open up the cupboard so that should help me rule out a supply issue as all the fuses are fine.

Cheers again.

 

[AndyPRK]

you will need to measure between earth and live with a meter to check polarity.

L to E 230V
N to E ~0V

 

[RF Lighting]

And L to N ~230V

 

[flameport]

Hopefully the cable was installed properly by the builders and it's just the eejit who installed the heater who got it wrong.

Rather more likely that the whole lot was installed by the 'builders' and no testing of any kind was done.

 

[ban-all-sheds]

Would it normally work if wired the wrong way round

It's an AC supply - the voltage between N & L varies from +325V to -325V and back again 50 times a second - there's no way the storage heater can tell that N & L have been swapped.

They should not be swapped though, because as flameport says that can leave the insides live when you think it's switched off, or live if a fuse or other safety cutout blows.

 

[justin1972]

Cheers all. A new switch and wired the correct way round has rectified the problem ... I now have heating again !

Flameport has probably hit the nail on the head about the builders installing it all with no testing involved. I bought the place new 20 years ago and it was all installed when I moved in ... all a bit worrying if that's the way the do things. Would love to think things have changed ... but probably not !

I shall highlight it to the other flats so they can check .. at least as it's economy 7 it's not live all the time (in theory)

 

[ebee]

"Would love to think things have changed ... but probably not !"

You should see the (poor) standards of some more recent ones.
Makes me shudder.

It is not uncommon for 1 home in 20 to get tested on new builds and all the certs get filled in with identical results.