Immersion heater tripping

[TheOriginalTonkaToy]

BAS is referring to the way that the cable has been terminated in the consumer unit - if that's wrong then you'll definitely need an electrician to have a look.

Does the switch that trips have a test button or not?

 

[bongos]

If your main CU has an RCD and your E7 CU does not, then if you have the neutrals at the immersion wired the wrong way round then the RCD on the main CU will trip when it switches from the economy supply to normal supply.

This is because the main CU is supplying the live feed but not returning the current through the same neutral. It is instead trying to return in through the E7 circuit neutral. This will lead to the L/N imbalance that trips the RCD.

 

[ban-all-sheds]

are you referring to the immerison wiring ?

Yes.

 

[Gaz the Sparky]

Can i just throw something in to the pot

Did you say that you installed a new horstman time clock?
How where the immertions wired up before was there just two switches?

the reason i ask is that the horstman timer just requires one feed from the normal tariff electric ie 24 hour supply it doesnt need the ecomany 7 supply.

There is a timer inside that brings on the lower immertion heater in the off peak times

if you have wired both the supplys into the same terminals of the time clock then you will get an inbalance and that will trip the rcd off.

hope this helps

G.T.S

 

[Bunters]

The original Tonka Toy wrote: "BAS is referring to the way that the cable has been terminated in the consumer unit - if that's wrong then you'll definitely need an electrician to have a look.

Does the switch that trips have a test button or not?"

The answer is yes, the switch that trips does have a test button.

 

[ban-all-sheds]

That's an RCD. It's tripping because of an imbalance between the live & neutral currents, most probably because when the E7 supply kicks in another neutral path gets created.

Double check all the wiring - make sure there are no cross-connections between the supplies to each element.

 

[Bunters]

Thanks Ban all Sheds

Gaz the Sparky has an interesting point :
"The reason i ask is that the horstman timer just requires one feed from the normal tariff electric ie 24 hour supply it doesnt need the ecomany 7 supply"

One thing's for sure... I need an Electrician.. way out of my depth!, but persevering out of sheer determination to understand how this all works.

Having looked an the CU, I can see i have two boxes, one with all the ring main up / down etc that also has an RCD with a test button!, the other (Economy 7) has three blocks marked storage heater 1 / 2/ 3, could I be mistaken that the immersion is economy 7 fed? how can I be sure of this?

If Gaz is correct that the hortsman just requires one feed, why is it called an 'Economy 7' timer, surely it would need to be fed directly from the economy 7 fede to benefit from this tarrif?

 

[Gaz the Sparky]

no the timer doesnt need an off peak suppy it has a timer in it to mimick the econamy 7

when the econamy 7 kicks in all the electric used in the house becomes cheap.

as i said before the normal tariff ie 24 hour supply shoud be used to supply the clock. The econamy 7 supply should be disconnected and made safe.

then there is the two connections for the two heaters the lower one in the tank is the off peak one and the higher one is the boost normal tarif one.

this could be your problem if you have connected both the normal tariff and off peak together because when the off peak becomes live theres an inbalance and the RCD trips out

Instructions are here http://www.just-heating.co.uk/PDFs/Electronic7-InstallationInstructions.pdf

Terminal 1 is normal tariff live in
Terminal 2 is normal tariff neutral in
Terminal 3 is both heater neutrals out
Terminal 4 is boost top heater live
Terminal 5 is off peak lower heater live

hope this helps
G.T.S

 

[Bunters]

Thanks very much Gaz - I think you have a really good understanding of my situation, I will have a look tonight and more than likely arrange for an electricain to come in.