On 19 Sep 2020 at 21:20:52 BST, "
wrote:

On Friday, 18 September 2020 20:21:30 UTC+1, Roger Hayter wrote:
On 18 Sep 2020 at 15:44:04 BST, "Andy Burns" wrote:

Max Demian wrote:

Keefiedee wrote:

What I really want to know is is there a timer out there which will
fit on the present single pattress AND has an outlet I can easily use
to connect to the wire from the immersion heater.

Can't you fit a 13A socket on the pattress? Then you can fit a standard
plug-in timer.

Immersion fed via a 13A plug?

Sure a 3kW is the same load as a kettle, but it'll be on for much
longer, plug and socket will get hot I'd imagine ...

Agreed. And I am not sure a cheap timer will be happy switching a 3kW load
regularly.

Millions of basic pin timers have been doing just that in immersion systems
around the country for decades.

Yes, timers to fit a single pattress are available.


NT

And much more appropriate than a plug-in one.
--
Roger Hayter

On Saturday, 19 September 2020 21:42:41 UTC+1, Dave Liquorice wrote:
On Sat, 19 Sep 2020 13:19:26 -0700 (PDT), tabbypurr wrote:

Yep, it's not so much the pins and sockets as the 13 A fuse.

Brand new SWFCU after feeding a 3 kW storage heater for not very
long, days/weeks.

https://www.flickr.com/photos/allsorts-60/12180205643
https://www.flickr.com/photos/allsorts-60/12179988825
https://www.flickr.com/photos/allsorts-60/12179991875

Hager, not some cheap no-name... All storage heaters now only
have
20 A DP illuminated switches for connection. Overlaod protection
is
the 16A MCB for each heaters 2.5 mm radial.

Ouch. Is that circuit RCDed?

No.

If not the immersion might be conducting through the water, overloading
the sfcu.

Unlikely, this was a feed to a night storage heater. B-)

Posted illustrate that the 13 A fuses that get "warm" when passing 3
kW for a few hours.

Plugs, sockets, FCUs etc are meant to handle that ok. But in reality they don't always. Like you I'd expect a hager to be ok.

Years ago we had an FCU that fed an immersion that had split open. With no RCD it took time to realise. The thing was overloading & cycling on & off due to overheating its stat. The FCU was ok with it thankfully, though discovered to be rather hot.


NT