DPDT relay connections

fog · Jun 8, 2012

Hi please can someone help on relay wiring. I have a dpdt relay of 30 amps(all 230v) i am using a central heating control to power the coil to turn relay on, as i understand i put the switched live and neutral to pins A1 and A2 from central heating control, to energise the coil to switch the power. Which is switched via coil operation from common terminals (live and neutral) to NC, (normally closed) to pass the power through the coil to turn load on? and i ignore the NO (normally open) terminals, is this correct?
A Double Pole Double Throw Relay comes with 8 terminal points.

The terminals are COIL, COIL, COM, COM, NO, NO, NC, NC.
never wired relay before can do with some help.
many thanks

spark 68 · Jun 8, 2012

Hi,

I have attached a generic diagram of a DPDT relay, this is shown in the un-energised state (the coil), the contacts will change state when the coil is energised, ie. the N/O will become closed, and the N/C will open WRT the common contact.

Edit: the terminal markings are just for reference, normally as you say the coil terminations are designated A1 and A2

Knobhead · Jun 8, 2012

With the information you give

1/ common 1
2/ coil L
3/ NO 1
4/ NC 1
5/ NC 2
6/ NO 2
7/ coil N
8/ common 2

The numbers are for an octal based relay.

If you don’t understand C, NO, NC you should be looking for a new job!

Guest111 · Jun 8, 2012

its simple,live and neutral from clock to coil 1and 2 to operate relay,live and neutral in connect to the commons and live and neutral out to the normally open terminals making sure you maintain polarity ie l to common 1 l out to n o 1 neutral to common 2 neutral out to n o 2