No Continuity Between Consumer Unit and Immersion Switch

[JonWilko1]

I've recently tried to flush my heating system and inadvertently managed to block the microbore pipes and boiler in the process. At least I had my immersion heater I thought. I have unfortunately found out that the immersion wasn't working either. My Dad brought around his electrical tester and we found that the immersion heater is working fine, however there is no continuity between the consumer unit and the point at which the wires meet with the switch in the airing cupboard. As a temporary measure I've put a plug on the immersion heater cable and plug it into a socket just outside the airing cupboard. The plug does however run hot after 30 mins as its only 13amp. With the unsightly wire as well coming out the door I do want to get it wired up properly again asap. I cannot work out what the issue is as if there is a break in the cables to the consumer unit wouldn't the RCD have tripped in the consumer unit, which it hasn't.

 

[JohnD]

No, it wouldn't.

Have you verified that the switch on the cable works?

And the MCB or fuse in the consumer unit is live under load?

A loose connection can burn away. Sometimes you see the voltage drop under load when the connection is poor.

A faulty connection is easier to find than damage to the cable, such as a drill or nail can cause.

What sort of "electrical tester" are you using?

 

[Murdochcat]

Does your dad know how to use his "electrical tester"?

You need to start with R1 + R2 and then R1 + RN to prove continuity of conductors.

Could there be another switch in the circuit? There are houses wired like this on a larges estate near me

 

[jurassic sparkk]

Please don't say you're testing for continuity with the switch open.

 

[JohnD]

Could there be another switch in the circuit? There are houses wired like this on a larges estate near me

Good point. There might even be a timeswitch.

 

[terryplumb]

When was the immersion heater used last ,and has any electrical work been done since then , particularly at the consumer unit ?

 

[sparkwright]

Somebody already suggested there could be a timer somewhere.

Also, there could be a secondary switch somewhere. Back in the day, it was fairly common to put a switch somewhere convenient such as in the kitchen.

Any mysterious switches anywhere?

 

[JonWilko1]

Yes the switch in the airing cupboard for the immersion heater works. I tested for continuity by putting live and neutral wires together where they come out the wall in airing cupboard and testing down at the consumer unit. I don't think there's anything in between the consumer unit and where the switch is in the airing cupboard. That's a good point though I'll have a look around for another switch.
The house is 20 years old and I moved in 2 years ago. As far I know it has never worked since I moved it, only now that I have wired a plug on it.

 

[JonWilko1]

There's a switch in the kitchen on a panel labelled 'Water Heater' which is off. I cant remember if we tested with it on or off. I think I'll have to re-test. Thank you for all your help here.

 

[JohnD]

Yes the switch in the airing cupboard for the immersion heater works. I tested for continuity by putting live and neutral wires together where they come out the wall in airing cupboard and testing down at the consumer unit. I don't think there's anything in between the consumer unit and where the switch is in the airing cupboard. That's a good point though I'll have a look around for another switch.
The house is 20 years old and I moved in 2 years ago. As far I know it has never worked since I moved it, only now that I have wired a plug on it.

I think you mean that the Supply side of the switch is connected to the supply at the Consumer Unit.

Does the supply side of the switch show 240volts?

What does the load side of the switch show?

 

[Murdochcat]

There's a switch in the kitchen on a panel labelled 'Water Heater' which is off. I cant remember if we tested with it on or off. I think I'll have to re-test. Thank you for all your help here.

That’s generally where they are on the Woking estate near me.

 

[ericmark]

My old house was also like that, with switch in kitchen and airing cupboard. This house there is a CT coil on the main meter tails and immersion only works when we have excess solar.