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teleman 1st November 2012 04:06 PM

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I know this is strictly a audio related forum,but would be grateful if someone could kindly help me this question.

I am trying to construct a small "Plastic heat bending Jig" to make some ABS plastic cases. I have bought a 15mm/300mm long heating rod element & want to wire it to an Oven type-10A/250v) Thermostat/ temperature control switch. However I'm not sure how I should wire these two.

The connection details given below.


AndrewT 1st November 2012 04:14 PM

Insulation of the mains terminations is very important.
Is the heating element for 220Vac or 220Vdc use?
Can you arrange to power up through an isolating transformer?

As to the switching.
Simply connect the switch contacts in series with the heater.
When the contacts are open the heater is OFF. When the contacts are closed the heater is ON.

But that will give quite large swings in temperature as the "system" cycles through the ON/OFF phases.
That may be good enough.
Proportional control is very much more complex. Avoid it if you can.

teleman 1st November 2012 06:46 PM

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Thanks Andrew,
Yes, I will insulate the terminations properly.
Both the h. element & the thermo/switch are rated for 220v ac only

Sorry,I don't have an isolation transformer....just want to keep it simple but want to be able work saftely.

I've worked how the switch works,but still confused as to how to wire these two in series...perhaps you could direct me please?


DF96 1st November 2012 07:32 PM

If 'connect in series' does not mean much to you then you should not be doing mains wiring.

Speedskater 1st November 2012 08:19 PM

While the heating element should not care whether it's AC or DC the control and switches might.

Enzo 1st November 2012 11:56 PM

"In series" is exactly how a table lamp is wired. In the case of the lamp you have a light bulb instead of a heating element.

gmphadte 2nd November 2012 05:58 AM

Don't electrocute yourself.

Gajanan Phadte

teleman 3rd November 2012 11:57 AM

3 Attachment(s)
Thanks guys for all your input...however, I think I've asked the wrong question! What tripped me off ( pun not intended!) was the terminal post 1

Whats's the purpose of terminal post 1?
Is the wiring as I've drawn correct?

AndrewT 3rd November 2012 12:22 PM

you are way out of your depth.
That switch is a double throw type. Sometimes described in the datasheet as spdt (single pole double throw).
It has a normally closed (NC) pair of contacts and a normally open (NO) pair of contacts.
You should have known this.
You should also have known that you can check which contacts are NC with a test instrument, or even a battery and bulb.
You should also know how to connect in series.
You should also know how to get the switch to change over.

This is all very basic electrics.
You do not learn this by experimenting with mains voltage on the LIVE side.

I suggest you get a qualified electrician to wire this up and "certify" that it is safe for your to use.

DF96 3rd November 2012 12:48 PM


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