Any electricians on the forum

[Oddjob]

Fairly sure there are a couple but I need some advice.

I've just had to replace one of my storage radiators, the one I removed just had a double pole socket running on economy 7, the new one needs not only that but a mains powered feed as well. Not a big problem as luckily this one is situated right next to a double ring main socket. However the new one has features the old one doesn't. As a result even though I've always done all my own electrics I'm not sure if what the manufacturers are saying is actually needed, I mean by that, it's brand new, surely they are making a safe product, why do they need you to test the insulation with a 500v test voltage? why do they need to check how many Kwh it's consuming on it's first charge for instance?

Here's a link to the installation manual, https://www.electricradiatorsdirect.co.uk/manuals/technotherm/Technotherm-TTB-E-Duo-Storage-Heater-Manual.pdf go to page 9 and have a read, let me know what you think, I've fitted at least 8 storage radiators and they've always been just wire in, switch on and open the windows as the bricks smoke like a bitch the first charge.

Let me know what your thoughts are please.

[AshimotoK0]

Probably just protecting their ar$e Ken.
Do you have a consumer unit with 30mA RCD's? If so you should have no worries. Mine kept tripping over Christmas because there was a bit of toasted teacake bridged between the metal frame and the heating elements.

[Oddjob]

The main fuse box is an RCD one but the economy 7 one is still an old MK Sentry fuse box, with popup fuses not the old fuse wire ones. I've been thinking about changing the fuse box for an RCD one for a while now and at the same time changing all the wires for brow/blue instead of the red/black they still have. Might do that soon. Even if I just change the box and the wire running to the new heater that would be a start.

[Sesman]

Testing at 500v is just to test final circuit cable insulation . Don’t test the actual appliance at 500V

[Oddjob]

What exactly are they testing though Phil, that the cables not cut?, earthing out or leaking somehow?

I’ve had all the sockets tested with some sort of meter which detects if it’s earthing etc, they all checked out fine.

I’ve totally rewired my house twice now, once to replace the old 1950 braided cable wiring with modern red/black solid core 2.5 t&e etc and then another when the single ring main that was fitted from new started to trip out with the demands made on it, now the house has 4 ring mains, up, down, kitchen and garage. Since doing that and replacing all the wires with the euro brown/blue stuff it hasn’t tripped except when the wife blew up the toaster. I didn’t change the economy 7 wires as most of them aren’t used these days, the house is well insulated and I don’t need as much heating as I used to. However I always intended to as I like to do the job right and those are the last red/black left in the house.

[AshimotoK0]

The main fuse box is an RCD one but the economy 7 one is still an old MK Sentry fuse box, with popup fuses not the old fuse wire ones. I've been thinking about changing the fuse box for an RCD one for a while now and at the same time changing all the wires for brow/blue instead of the red/black they still have. Might do that soon. Even if I just change the box and the wire running to the new heater that would be a start.

Deffo worth fitting an RCD Ken.

[McCabe-Thiele (Ted)]

The main fuse box is an RCD one but the economy 7 one is still an old MK Sentry fuse box, with popup fuses not the old fuse wire ones. I've been thinking about changing the fuse box for an RCD one for a while now and at the same time changing all the wires for brow/blue instead of the red/black they still have. Might do that soon. Even if I just change the box and the wire running to the new heater that would be a start.

Deffo worth fitting an RCD Ken.

I fitted a split load type Consumer Unit some years ago so I could fit trip fuses on both sides but retain some none RCB/RCD function for the Garage supply,freezer & upstairs lighting - it was supposed to mean that in the event of a fire you could find your way out of the house. When we had our house fire that started in the loft/eaves it worked for less than a minute before the main fuse in the meter box blew.

[Oddjob]

Just ordered a new fuse box with 7 RCBO type fuses. Might as well do it right in the first place. I'll replace the run of wire to the new heater and do the rest later this year whenever I have the floorboards up.

[BigAl (Alan)]

Ken, what size dual storage heater did you purchase? You also referenced a double pole switched 'socket'...should this be '20amp switch'?

[Oddjob]

I bought the 3.4kw heater Al and it's running off a MK 13 Amp Switched Fused Spur Flex Outlet and Neon - White

https://www.tlc-direct.co.uk/Products/MB1070.html?source=adwords&ad_position=&ad_id=&placement=&kw=&network=x&matchtype=&ad_type=pla&product_id=MB1070&product_partition_id=&campaign=shopping_excluded&version=finalurl_v3&gad_source=1&gclid=Cj0KCQiAhc-sBhCEARIsAOVwHuSmNC1TgAgfmAzUyOpOC9rxFNgzC_apSsX6DG0TgDCA0tfJb10WIjkaAoxDEALw_wcB

[BigAl (Alan)]

Replace the switched fused spur to a 20amp DP switch...the fitted 13amp switched fused spur is a little undersized for the 3.4k/watt heater. This circuit should also be connected to a 20amp mcb within the off-peak/night rate consumer unit.
The other 24 hour heater circuit can be connected to the ring-main via a 13 amp switched spur...or better still a dedicated 16amp mcb circuit from the 24 hour consumer unit.
Do you have assess to an insulation tester & earth fault loop impedance tester?

[Oddjob]

Yes Al, I have access to those or should I say I have mates who have them. I intend to ask one to pop over and check my work after it's done.

TBH I thought the 13amp fuse would be sufficient Al, you used to get 3.4kwh fires running off a 13amp plug. I'd prefer for the fuse to blow before it starts melting the contacts inside the socket, saying that I'd say the RCB would trip long before that happened. However if you think a 20amp one would be better I can do that easily.

How many spare outlets for fuses do you think I have?    I'm all electric, no gas at all. The main fuse board is bloody huge already and they are all taken up now.

TBH the 24h side just charges a small battery for the LCD panel and powers the convector heater fitted to the inside in case the heating charge in the bricks runs low and the heater feels it needs to boost the temp. Hopefully that should rarely be on. That's my understanding of it anyway, I don't think it has the ability to power the elements inside the bricks.

[Seabeowner]

My father was all electric with storage heaters. Presume each is on its own spur and remember each was on a switched 20amp dp switched outlet. Also one had an integral fan on a thermostat that was wired into the ring I believe.
I also dismantled one from my gran and put the bits is my car and re-installed it in my father's extension.

[Oddjob]

Yeah, mine are also each to their own spur.

I've ordered some 20a DP switch spur sockets, this time without a fuse.

You are correct BTW Al, as I suspected you would be, looking it up on the web the advise was anything rated above 3Kw should have it's own spur etc, as it turns out the rest are all 2.6kwh heaters so that doesn't apply.

The general consensus on the web from various electricians is to use either a 20a or 16a MCB, I've opted for RCBO instead of MCB as I understand they are even better. The existing fuses are all 16a MCBs so I opted for the 16a RCBO instead of the 20a RCBO.

Any thoughts?

I'd rather you say something than nothing, I'm not a novice at electrics but up to date regs aren't my forte.

[BigAl (Alan)]

All sounds good. RCBO’s are the preferred method for overload & short-circuit protection. Again, ask your friend to check the tripping times of the RCBO’s to confirm that devices operate at safe levels.