Contactor for oven

[Bradley6969]

Hi, working on a job, guy wants all appliances on grid switch, the oven needs 32amp supply so best way I can think of is 6mm into contactor 6mm to cooker then 1.0mm from contactor to 20amp DP in grid switch to keep it on grid???
Thing confusing me is the grid is on a 4mm 32amp at the moment and the 6mm will be from a 32amp MCB but that will mean the DP controlling contactor is on one circuit and oven fed between contactor is on another
Thanks

 

[Andy78]

Search for click minigrid. They do a 32A DP grid switch.

 

[buzzlightyear]

6mm to cooker then 1.0mm from contactor to 20amp DP in grid switch to keep it on grid

?????? three words

 

[goasis]

"6mm will be from a 32amp MCB but that will mean the DP controlling contactor is on one circuit and oven fed between contactor is on another"

Maybe I'm misunderstanding but isn't that the whole point?

 

[davesparks]

Hi, working on a job, guy wants all appliances on grid switch, the oven needs 32amp supply so best way I can think of is 6mm into contactor 6mm to cooker then 1.0mm from contactor to 20amp DP in grid switch to keep it on grid???
Thing confusing me is the grid is on a 4mm 32amp at the moment and the 6mm will be from a 32amp MCB but that will mean the DP controlling contactor is on one circuit and oven fed between contactor is on another
Thanks

That's one of the reasons contactors exist, to be able to use one circuit to control a different circuit without them being linked.

The switch operating the contactor obviously won't be directly connected to the 4mm 32A circuit anyway, you'll have a smaller ocpd protecting the 1.0mm and the contactor won't you?

 

[Bradley6969]

That's one of the reasons contactors exist, to be able to use one circuit to control a different circuit without them being linked.

The switch operating the contactor obviously won't be directly connected to the 4mm 32A circuit anyway, you'll have a smaller ocpd protecting the 1.0mm and the contactor won't you?

The 6mm will be on a 32a MCB so my supply circuit for oven, and the 1.0mm controlling the switching on the contactor was going to come from the 20amp DP in grid switch which is on a 4mm 32amp radial?
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"6mm will be from a 32amp MCB but that will mean the DP controlling contactor is on one circuit and oven fed between contactor is on another"

Maybe I'm misunderstanding but isn't that the whole point?

Yes sorry it’s more to do with the 6mm into contactor and out to oven is on 6mm 32amp MCB then the 20amp DP controlling the contactor is on a 1.0mm but will be on the 4mm 32amp radial for grid switches?

 

[suffolkspark]

Sounds a pointlessly messy setup just use the click grid as Andy sujested

 

[Bradley6969]

Sounds a pointlessly messy setup just use the click grid as Andy sujested

All bought now can’t get one for today

 

[davesparks]

The 6mm will be on a 32a MCB so my supply circuit for oven, and the 1.0mm controlling the switching on the contactor was going to come from the 20amp DP in grid switch which is on a 4mm 32amp radial?

There must be another fuse there somewhere, you can't just connect 1.0mm and a contactor directly to a 32A circuit!

Also how often is the customer intending to switch the cooker on and off? I assume you've confirmed they only turn it on to cook and won't be leaving it on 24hours a day? If not then how long do you think that contactor is going to last?

 

[Bradley6969]

There must be another fuse there somewhere, you can't just connect 1.0mm and a contactor directly to a 32A circuit!

Also how often is the customer intending to switch the cooker on and off? I assume you've confirmed they only turn it on to cook and won't be leaving it on 24hours a day? If not then how long do you think that contactor is going to last?

The 1.0mm is only Switching the contactor?
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The 1.0mm is only Switching the contactor?

Through a 20amp DP I’ll use 2.5mm it’s only switch through the DP

 

[davesparks]

The 1.0mm is only Switching the contactor?

Yes, but 1.0mm can't be protected by a 32A MCB and your posts so far suggest that this is what will happen.
Also protecting the contactor coil with a 32A MCB is not a good plan either.

Why not fit a 1A fuse or MCB in the enclosure next to the contactor, feed it from the cooker supply and use the 1.0mm from the grid switch as L and S/L?

 

[DPG]

The 1.0mm is only Switching the contactor?
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Through a 20amp DP I’ll use 2.5mm it’s only switch through the DP

20A switch yes, but isn't it fed from a 32A RFC?

 

[Bradley6969]

20A switch yes, but isn't it fed from a 32A RFC?

All the grid is on a 4mm radial 32amp in and out each fused appliance the contactor will be switched of the 20amp DP which is on the 4mm radial? With 2.5mm??
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Yes, but 1.0mm can't be protected by a 32A MCB and your posts so far suggest that this is what will happen.
Also protecting the contactor coil with a 32A MCB is not a good plan either.

Why not fit a 1A fuse or MCB in the enclosure next to the contactor, feed it from the cooker supply and use the 1.0mm from the grid switch as L and S/L?

Oh I see so I can’t protect the coil with the 20amp DP fed from 32amp radial?

 

[DPG]

But you said the 1mm contactor coil feed was going to be taken from the RFC. The RFC is protected by a 32A device is it not?

 

[suffolkspark]

Literally this is such a muddle... why not just order the 32A dp switch which is perfect for the job, electrical2go sell them, and then go back and swap, I'd put it on the 20A dp you have for now and put a 20a mcb in?

 

[Bradley6969]

But you said the 1mm contactor coil feed was going to be taken from the RFC. The RFC is protected by a 32A device is it not?

Yes I see now, so if I put the 20amp DP on a 20amp MCB send a 2.5mm 3 core from contactor to 20amp DP so will have Perm L from MCB and SL to contactor cool and N which isn’t needed which will just go straight to contactor
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Literally this is such a muddle... why not just order the 32A dp switch which is perfect for the job, electrical2go sell them, and then go back and swap, I'd put it on the 20A dp you have for now and put a 20a mcb in?

It’s bought now, plus I’m working with a sparky anyway I’m not qualified but doesn’t seem to know hence why I’ve asked on here

 

[Spoon]

It’s bought now, plus I’m working with a sparky anyway I’m not qualified but doesn’t seem to know hence why I’ve asked on here

Why are you not asking the sparky who you are working with?

 

[Bradley6969]

Why are you not asking the sparky who you are working with?

He’s a subby so ain’t intersted in showing me

 

[westward10]

As previously stated the control circuit (coil) requires circuit protection. Fit a spur next to the contactor enclosure or a fuse within. Connect the fuse from the incoming supply at the contactor (neutral direct to the coil) then a two core to the grid switch to switch the line for the coil.

 

[DPG]

How come you have been paired with someone who is not interested in helping you learn things while you get qualified?

 

[Bradley6969]

As previously stated the control circuit (coil) requires circuit protection. Fit a spur next to the contactor enclosure or a fuse within. Connect the fuse from the incoming supply at the contactor (neutral direct to the coil) then a two core to the grid switch to switch the line for the coil.

So new supply to spur? 6a mcb do?
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How come you have been paired with someone who is not interested in helping you learn things while you get qualified?

He’s subbing to us first time I’ve worked with him
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So new supply to spur? 6a mcb do?
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He’s subbing to us first time I’ve worked with him

So I can’t link from existing cooker supply which goes to contactor for my spur? This is on 32amp mcb

 

[Lucien Nunes]

Oh I see so I can’t protect the coil with the 20amp DP fed from 32amp radial?

What's a 20A DP? A switch? Switches don't protect anything. In any case, no. A bare contactor is a panel component, not a complete appliance, so it doesn't have its own OCPD built in. You are expected to provide it as per the manufacturers' specs. Some ready-built contactors-in-enclosures bought off the shelf have the fuse included for your convenience.

Normal practice is to put say a T1A 5x20mm HRC cartridge in a DIN-rail mounted fuse terminal next to the contactor, fed from the contactor's main circuit. Then run a 1.0mm² control circuit L & SL to the gridswitch. Because there will then be two supplies in the gridswitch in a situation where this would not be expected, I would label this inside the grid.

Alternatively, you could fuse down a feed from the general appliance circuit, using say a 3A fuse in the grid, control it with a switch, and send SL & N to the contactor box. Make sure that the contactor would be adequately protected by such a fuse. As there would then be two supplies present in the contactor box, I would label that instead. Or, you could send an unfused feed from the control switch in suitable cable (e.g. 2.5mm² if that is adequately fault-protected by the 32A MCB) and add the fuse in the contactor box, which turns it into a fixed load that avoids having to protect the control cable run against overload.

 

[westward10]

Similar to this, excuse my schematics.

 

[PEG]

By the time we've decided on the layout,i've lit the bbq,and am already 4 sausages,ahead...?

 

[Bradley6969]

Similar to this, excuse my schematics.View attachment 54380

Spot on thanks, so link to the spur from cooker supply to contactor what size would that be? As that will be still protected by 32amp breaker although there’s no load on it?
Thanks
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What's a 20A DP? A switch? Switches don't protect anything. In any case, no. A bare contactor is a panel component, not a complete appliance, so it doesn't have its own OCPD built in. You are expected to provide it as per the manufacturers' specs. Some ready-built contactors-in-enclosures bought off the shelf have the fuse included for your convenience.

Normal practice is to put say a T1A 5x20mm HRC cartridge in a DIN-rail mounted fuse terminal next to the contactor, fed from the contactor's main circuit. Then run a 1.0mm² control circuit L & SL to the gridswitch. Because there will then be two supplies in the gridswitch in a situation where this would not be expected, I would label this inside the grid.

Alternatively, you could fuse down a feed from the general appliance circuit, using say a 3A fuse in the grid, control it with a switch, and send SL & N to the contactor box. Make sure that the contactor would be adequately protected by such a fuse. As there would then be two supplies present in the contactor box, I would label that instead. Or, you could send an unfused feed from the control switch in suitable cable (e.g. 2.5mm² if that is adequately fault-protected by the 32A MCB) and add the fuse in the contactor box, which turns it into a fixed load that avoids having to protect the control cable run against overload.

Thanks you’ve put that well I understand now sorry I’m still learning the best way

 

[westward10]

It won't need to take 32A as the load is dictated by the fuse for the control circuit. You need to ensure differing conductor csa at the contactor terminals are sound.

 

[Bradley6969]

It won't need to take 32A as the load is dictated by the fuse for the control circuit. You need to ensure differing conductor csa at the contactor terminals are sound.

32A MCB 6mm in and 6mm out contactor to oven, 1.5mm from supply 6mm at contactor to fuse spur then 1.0mm to 20amp DP grid switch, L from Spur and SL back to A1 terminal with N link from load side of spur back to A2, sorry I appreciate your help just wanting to understand

 

[davesparks]

32A MCB 6mm in and 6mm out contactor to oven, 1.5mm from supply 6mm at contactor to fuse spur then 1.0mm to 20amp DP grid switch, L from Spur and SL back to A1 terminal with N link from load side of spur back to A2, sorry I appreciate your help just wanting to understand

The neutral can come straight from the supply side of the contactor to A2.

This still doesn't address the question of whether this contactor will be left on 24/7 or only switched on when the cooker is being used?

 

[Bradley6969]

The neutral can come straight from the supply side of the contactor to A2.

This still doesn't address the question of whether this contactor will be left on 24/7 or only switched on when the cooker is being used?

Only when in use, they have a gas oven so this is only being used when they have more people round at one time

 

[davesparks]

Only when in use, they have a gas oven so this is only being used when they have more people round at one time

That's ok then, if its left on 24/7 that contactor won't last long!

 

[Bradley6969]

That's ok then, if its left on 24/7 that contactor won't last long!

Thanks hahahaha, sorry I’m still learning appreciate all the help

 

[westward10]

32A MCB 6mm in and 6mm out contactor to oven, 1.5mm from supply 6mm at contactor to fuse spur then 1.0mm to 20amp DP grid switch, L from Spur and SL back to A1 terminal with N link from load side of spur back to A2, sorry I appreciate your help just wanting to understand

As Dave says and shows in my drawing the neutral can go direct to the coil from the supply neutral. Only the line need go through the spur/fuse.

 

[freddo]

There must be some space somewhere to jam a Slydlok fuse holder with a 2A fuse!

 

[PEG]

I bet that oven has a clock and a timer...you just know,someone is going to leave that coil cooking