outdoor heater circuit with pir....

[reese646]

would this one by maplins do the trick?

its a

30A SPDT Power Relay

​

 

[bugsy]

You even want to consder going wirelss, Wise do PIR's for £40.00 and 1 channel switch receivers for £ 30.00 ( 1000w)

 

[reese646]

right had a look around and have come up with this...

but is it ok to have the pir on the same feed? also, would the pir have a nuetral? or would you return of the terminal on the relay? have also put a junction box in to help out on cable runs, how does this look now any closer? never used relays before so learning as I go, any comments would be appreciated

 

[sparks1234]

Use an Occupancy detector instead of a PIR, it wont keep going off like a PIR.

An occupancy sensor is just a posh PIR, no advantage of using one, it would probably be easier to fix a PIr to something like a gazebo

 

[reese646]

any advances on the actual wiring lol

 

[reese646]

need advice on relays and circuit

hi I started another thread on this but kinda got sidetracked, I'm making an outdoor heating areaas follows

it has an on/off for the system, it has a p.i.r. to turn the heaters on/off when the system is enabled, it also has a 2G switch to allow heater 1, heater 2 or both to be used depending on how cold it is and where we're sitting within the gazebo, these are the fact, and I'm not interested in changing anything around other than using more suitable versions of the same

the heaters are both 1.5kw units and the pir was a 3kw max one but someone suggested using a relay which I've never used before, so hence I've come up with this and want to know if its ok?? if so what sort of relay would I need, 30a i guess but SPST, SPDT, DPST, DPDT?? and how would the pir be wired in said circuit? how I've wired it in the diagram or not? and lastly, if a relay is used is there any need for the 3kw pir which are quite expensive, could I just use a cheap low wattage one instead??

best drawing I could do lol, appreciate any help

 

[bugsy]

Re: need advice on relays and circuit

Why use a relay instead of contactor ?
and your only switching the coil so no load

Thats with regard to the pir

 

[benji]

Re: need advice on relays and circuit

personally i would use 2 relays one for each heater

yours benji

 

[COLLY]

you will have a lot of nuisance with the pir eg wind and cats and dogs although im sure you can isolate it when not in use personally the time lag sounds like a good option or a time clock and contactor enclosed in an ip65 enclosure

 

[uksel]

electric heaters (especially infra-red) can be quite demanding (with regard to current).

make sure that the switches you are using, including the PIR are have the appropriate current ratings

 

[Davey101]

I wouldnt advise a non-spark to do this sort of work, but you seem pretty clued up (and will do it anyway), so here goes-

Get yourself a suitable enclosure, with a din rail mounted inside. Mount your contactor inside this, along with some din rail connectors, such as- Wire Connection*:*DIN Rail Mount Connectors Make sure you get the end caps as well, and be sure to mount them the right way round, so the live side of one connector goes against the insulated side of the next-you'll see what I mean when you use them.

Get some plastic CTS glands for the cable entries. Run ALL the cables to this enclosure, dont mess about with joint boxes. Then connect it all together.

Personally I would have the switch side of the PIR feeding a coil of a contactor. Then take your feed into the contactor,and back out to the feed side of a 2 gang switch (I think MK do a 2 gang masterseal switch). Then just connect the switch returns from the switch to your heaters.
The PIR will still activate the contactor, but the heaters wont be on if the switchs are off. If you want to be able to turn everything off, just wire another switch into the feed to the PIR.
The advantage of wiring to the enclosure is that you can connect it how you want to.
A 2 or 6 amp mcb to feed the PIR may be needed, depending on the supply to it.
All the above is presuming that you have selected the correct size cable, switchs, contactors etc, and the PIR and cable feeding it are suitably rated for the MCB protecting it.

What size are the heaters you are using?

 

[reese646]

there 1.5kw, two of them, if a contactor is used, which one should I use, my electrical knowledge is ok, just never got into more advanced switching before, get the idea, just not 100% on what epuipment to actually use, a reference to a screwfix/maplins product would be handy

Also could I feed the pir from the same feed that feeds the contactor and the heaters?

 

[reese646]

Re: need advice on relays and circuit

hi, thanks for the replies, could you point me in the right direction of the contactor/relay that I should be using, a maplins/screwfix product would be handy, and don't want a relay per heater as I want to be able to control the heaters manually after they've been powered

Also how does the wiring in the pic look? anything look wrong or out of place, best to chesk ?

 

[xraytek]

Re: need advice on relays and circuit

hi, thanks for the replies, could you point me in the right direction of the contactor/relay that I should be using, a maplins/screwfix product would be handy, and don't want a relay per heater as I want to be able to control the heaters manually after they've been powered

Also how does the wiring in the pic look? anything look wrong or out of place, best to chesk ?

Something like this will do:

40 Amp 2 Pole Contactor - 3 Module

And do you really need 2 switches (one for each heater)?
You could have a main on/off switch, and a second switch for running 2 heaters.
Something like this for example:

 

[uksel]

Lucky for you i've had a lot of free time on my hands tonight..

your current demand works out to be about 13Amps, so before you start i'd recommend a 16A RCBO

then instead if a switch, because of the load, and for the functionality i would recommend a DOL starter (Direct on line starter) rather than play about buying din rail and contactors etc.

this would do the trick ABB | Control Gear | Control Gear and Switchgear | Motor Starters / Accessories | DRB6, DRB7 - Motor Starter in a insulated housing |GJK1274156R5601

make sure you check the max load of the device and the IP rating to be sure it suits your needs

i would run the supply to an IP rated moulded junction box at high level, have some PVC conduit coming out each end to feed the heaters (have some 2.5mm flex come from a conduit through box to the heater itself, or use kopex if you want to maintain the single cables through out)

out of the moulded box I would feed down to the direct on-line starter and this would effectively be your switch (make sure the contactor is switched in line

pretty much look at the diagrams that i have made up for you and holla if there is anything you dont get



don't forget the tanks if this helps you plz