Contactor for outside heaters

[Bradley6969]

Hi looking for some advice, looking to put some outside heaters (in my garden) 2 x 2500w, now I want a time delay switch but this can only switch 16A, so I’m looking at putting a contactor in as I already have one, but I’ve only ever used contactors twice before, is this the best way to set up and is drawing fine?
Thanks

 

[telectrix]

looks good from here. i assume you omitted the earthing from the diagram for clarity?

 

[Bradley6969]

looks good from here. i assume you omitted the earthing from the diagram for clarity?

Yes I did, wanted to check there was no easier way, my only problem is my contactor will be next to fuse board but the switch is far so I may be best just running a 3 core to switch as I don’t really want to run 2 cables
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Also is there anything on here or sites where I can gain some understanding of contactors as I’ve only used a few times wanted to learn about them a bit,
Also when using a contactor do you have to have control circuit and supply on different circuits? As example 32amp all on same circuit 4mm to contactor then say 1.5mm to delay switch then 4mm to heaters is there an issue with that as delay switch is not control the load and cable is only switching the contactor
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Or is the way to have a control circuit and supply?

 

[radiohead]

You can either have a separate control circuit at 6a, or loop from the live side of the contactor and feed through a 6a device. If the contactor is in an enclosure I would just mount a 6a mcb alongside on the din rail. You could also run two load cables to the contactor and run through separate poles which may reduce cable size over looping one heater from the other.
Can I respectfully suggest 5Kw of heat outdoors is maybe not very environmentally responsible, cant you just put a cardy on?

 

[Bradley6969]

You can either have a separate control circuit at 6a, or loop from the live side of the contactor and feed through a 6a device. If the contactor is in an enclosure I would just mount a 6a mcb alongside on the din rail.
Can I respectfully suggest 5Kw of heat outdoors is maybe not very environmentally responsible, cant you just put a cardy on?

So 4mm to say number 1 on contactor loop to 6a then that’s my control circuit? So never just have one circuit for supply and control then? Sorry appreciate your help and what’s cardy it won’t be used all the time mainly on summer nights when it’s colder

 

[radiohead]

So 4mm to say number 1 on contactor loop to 6a then that’s my control circuit? So never just have one circuit for supply and control then? Sorry appreciate your help and what’s cardy it won’t be used all the time mainly on summer nights when it’s colder

If you loop from the incoming live for your control supply it is still one circuit, it's just that if your supply is at 32a you'll need to provide a lower rated device for fault protection for the control part of the circuit if that's wired in 1.5mm. You could also feed the control circuit from a completely separate device in the DB, then there would be two circuits, the heater and control circuits. Generally simpler to keep it as one, with the control part sub-fused. Also means the whole lot isolates from one device at the DB

 

[Bradley6969]

If you loop from the incoming live for your control supply it is still one circuit, it's just that if your supply is at 32a you'll need to provide a lower rated device for fault protection for the control part of the circuit if that's wired in 1.5mm. You could also feed the control circuit from a completely separate device in the DB, then there would be two circuits, the heater and control circuits. Generally simpler to keep it as one, with the control part sub-fused. Also means the whole lot isolates from one device at the DB

Thanks mate understand it better now, as you say the contactor will most likely be within an enclosure so can be fused in there, plus I only have 1 MCB spare in my fuse box hahahaha
Thanks again everyone

 

[DPG]

No wonder the planet's in trouble.

 

[wrpizza]

Hi looking for some advice, looking to put some outside heaters (in my garden) 2 x 2500w, now I want a time delay switch but this can only switch 16A, so I’m looking at putting a contactor in as I already have one, but I’ve only ever used contactors twice before, is this the best way to set up and is drawing fine?
Thanks

Hi Bradley,

I read your post and I just wanted to make sure the contactor you already have is a NO (Normally Open) contactor. I'm not overly familiar with them either but I thought that's something to check before you start the job.

Regards

 

[davesparks]

I'd be inclined to have 2x 16A circuits feeding the heaters, both switched by the contactor.
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You can either have a separate control circuit at 6a, or loop from the live side of the contactor and feed through a 6a device. If the contactor is in an enclosure I would just mount a 6a mcb alongside on the din rail. You could also run two load cables to the contactor and run through separate poles which may reduce cable size over looping one heater from the other.
Can I respectfully suggest 5Kw of heat outdoors is maybe not very environmentally responsible, cant you just put a cardy on?

Why 6A for a control circuit? I normally go for 1A for a small number of contactors.

 

[Bradley6969]

I'd be inclined to have 2x 16A circuits feeding the heaters, both switched by the contactor.
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Why 6A for a control circuit? I normally go for 1A for a small number of contactors.

I only have 1 spare way in my fuse board, but understand what your saying, and I presume he was just making the point about 6A MCB as I have drawn it on my drawing, I’ve seen the 1A fuses you can buy makes more sense but it makes no difference either way

 

[telectrix]

Can I respectfully suggest 5Kw of heat outdoors is maybe not very environmentally responsible, cant you just put a cardy on?

says the man with a barbeque and a 5kW hot tub.

 

[Zerax]

No wonder the planet's in trouble.

I agree... if someone can afford to heat a garden with a 5kW heater... we urgently need to increase the price of electricity !

 

[Bradley6969]

Hahahaha oh well

 

[davesparks]

I only have 1 spare way in my fuse board, but understand what your saying, and I presume he was just making the point about 6A MCB as I have drawn it on my drawing, I’ve seen the 1A fuses you can buy makes more sense but it makes no difference either way

It does make a difference, and it doesn't have to be a fuse, a 1A MCB is fine.