Another STC-1000 wiring question

[finnfb]

Im attempting to build a heating and cooling STC1000 system using the below setup.


The plug sockets iv got for the heating and cooling elements is a double wall socket with switches. However, its a single pole setup
(ignore the poor cutting out)

Am I right in thinking this wouldn't work and I would need a double pole switch, or two separate ones?

[Blackaddler]

Use 2 separate sockets.

Edit. Suggest that you check screwfix.

I used these. [70p each at the time].

Now on clearance at 10p each, if you can find some instore at your local branch!

Here's how they look.

[Hairybiker]

One Q. Why use a 30A relay and a 13A socket?
If it is for a kettle element/2KW type then the standard relay in the unit works fine. If you are wiring something more than 3KW then you can't use a 13A socket/plug.

[finnfb]

Thanks for the replies. I'll have to see if theres a screwfix local to me, think i can rummage up 20p from the bank balance.

regarding the Amp question, i was following the advice from another thred on this forum who states:

this circuit assumes connection via a normal 13A plug with a 13A fuse in and so should supply no more than 13Amps or a 3Kw load. The use of a higher rated relay (such as the 30A maplins one) does NOT increase the maximum that can be drawn from a domestic plug for supplying the heating element, the extra switching capacity of the relay is merely a margin for safety; it is prudent to have such a margin in order to maintain the relay's contact life whilst switching the heavy, difficult loads it may experience (it can very briefly experience much higher initial currents as it makes the contacts to supply power to a cold element).

[Andy]

Good advice too. I've done the same on my HLT heater, use a STC1000 type device to switch a 30A mechanical relay that performs the switching of the 3kW element.

[Blackaddler]

Thanks for the replies. I'll have to see if theres a screwfix local to me, think i can rummage up 20p from the bank balance.

Screwfix store locator

[weetabixface]

Since your element is going to draw the most current is sensible to make the live mains connection direct to that, point 4 in your circuit diagram, then take a spur form there to connect to the STC live connections

W

[Fil]

leggo brick connectors make the wirring less fraught as the stc1000 terminals are a pita to use to grip more than one thicker hi load carrying live wire..