Help needed with Economy.

[a12jpm]

Replacing some old storage heaters for a customer at the moment. Using current FCU's at heaters for nice new panel heaters. These all lead back to a seperate CU with each heater on it's own MCB.

Now even when I isolate at this board I still get power at FCU's at certain times of the day, therefore I assume it's economy 10 and not economy 7.

Am I missing something or is it possible to just change the feed into this CU so that these panel heaters will have power all the time or are these FCU's normally wired with some kind of switch between CU and outlet.

Thanks in advance.

 

[Andy™]

there is normally a second CU with a switched supply. you may have either 1 meter with 2 live outputs (1 perm, 1 switched), or 2 meters. for testing purposes, you could take a feed to second CU from main CU. also be aware that many larger storage heaters are over 13A and often wired via 16/20A MCB and 20A DP switch

 

[Lurch]

Something's not right there. If they are fed directly from the CU you isolate they should receive no power at any time of the day. If there's any switching to be done it should be done pre-CU so isolating it should isolate the FCU's.

I would look into it further as there's something not very conventional going on, either that, or the CU you thought was off peak, isn't.

 

[Apache]

Some storage heaters have a boost supply for daytime extra heat so have 2 live feeds. Not one of those?

 

[a12jpm]

Sorry:

2 meters with 2 lives, 2 CU's with heaters on seperate CU.

This is what is throwing me. They should be isoalted when the CU is isolated so they must be getting a feed from somewhere else.

I was doubting my self and kept going round in circles and thought there must be a wise old head on here somewhere that would point out the obvious mistake i was making. I get the feeling there is a bit more investigation work to be done here.

 

[Lurch]

Some storage heaters have a boost supply for daytime extra heat so have 2 live feeds. Not one of those?

Should have 2 FCU's for the 2 supplies if that was the case, assuming it was done properly that is.

 

[a12jpm]

Some storage heaters have a boost supply for daytime extra heat so have 2 live feeds. Not one of those?

Ahh, that would make sense. I noticed a boost button on the front of the Economy 10 meter.

Cheers for that.

 

[Lurch]

Ahh, that would make sense. I noticed a boost button on the front of the Economy 10 meter.

It doesn't though, because if you've isolated the CU that feeds the FCU's they shouldn't randomly become live.