Quick check on cable size

[RickH]

Running in a T&E cable for an oven only (no hob)
This is rated as 5.9KW ..... so therefore 26A

Quick look up for a clipped direct (method C) cable on a 3m run shows that 4mm2 is more than beefy enough at 37A

That all correct ?

 

[flameport]

Yes, provided it's a 32A circuit breaker.

 

[RickH]

Might have to re-think this a bit.
There is a radial cct out to an MK Grid switch which is rated at 20A, this is in 4mm2 running from a 20A breaker. form the switch 4mm2 cable to a wiring connection point.
Previous oven was always hapy on the 20A breaker.

As Max capacity of this is 26A .... I need to find a solution for this Grid switch.

 

[AndyPRK]

there is a youtube video on this coming soon!

Fitting a contactor near the consumer unit to switch the oven (or hob) on and off. Clunk!

Personally I consider it a crazy situation, just so a grid switch can be used!

 

[RickH]

I can't find a Grid switch higher than 20A ..... I know I could increase breaker to 32A ... but would then need higher capacity grid switch
Anybody any suggestions ?

So far only thought is I would need to put a link in bypassing the GRID switch (and fit a blanking plate) and put a DP cooker switch instead of MK5045 connection point.
Unless anyone else has a better idea.


If my idea is the option what in neatest way to 'bridge' the 4mm t&e ... use WAGO connectors ...
https://www.tlc-direct.co.uk/Products/WA412C.html They are good for 32A
or WAGO push connectors rated at 40A
https://www.tlc-direct.co.uk/Products/WA173.html


Anybody experience of using these ? which is easiest to use ... or is there a better way

Connection will be within confines of the 'back box' so all still protected.

 

[RickH]

OK .. thanks, always thought DP local switch was requirement ... maybe as you see so many cooker switch boxes.

 

[flameport]

I can't find a Grid switch higher than 20A

https://www.cef.co.uk/catalogue/products/search?q=mini grid 32A

 

[RickH]

Unfortunately that would not be compatible with MK Grid system

 

[sparkwright]

What else does the grid switch serve?

Are you not running a new separate supply for the oven then?

 

[RickH]

No exisiting 4mm2 cable is big enough

 

[AndyPRK]

watch from 4 minutes

 

[sparkwright]

What else does the grid switch serve??

 

[Taylortwocities]

Hmm. Quite a few cables zig zagging in that stud wall. May be >50mm deep though, but doesn’t look kosher to moi.

 

[daggermark]

Hmm. Quite a few cables zig zagging in that stud wall. May be >50mm deep though, but doesn’t look kosher to moi.

That was exactly my thought. I'm not convinced they are deep enough, and they certainly aren't in safe zones.

 

[eveares]

My issue with using a contactor with a remote switch without also using a standard DP isolator is what happens if the contactor gets jammed on. Note that you would not use a domestic DP switch for safe isolation either as you can not lock them off normally.