Redundant 6mm Cooker circuit to 4mm radial?

[Noob2013]

Hi there.

Just a discussion with a colleague.

Is it acceptable to use a redundant 30A cooker circuit wired in 6mm, and downsize to 4mm via JB for a kitchen radial?

For example, if there is one ring supplying a house and you would like to reduce the risk of overloading with all the kicthen appliances.

Obviously new circuit is the best option but would this be acceptable?

Cheers

 

[Andy78]

30A existing circuit you say ? Is it a BS3036 OCPD ?

 

[Pete999]

Hi there.

Just a discussion with a colleague.

Is it acceptable to use a redundant 30A cooker circuit wired in 6mm, and downsize to 4mm via JB for a kitchen radial?

For example, if there is one ring supplying a house and you would like to reduce the risk of overloading with all the kicthen appliances.

Obviously new circuit is the best option but would this be acceptable?

Cheers

What sort of JB do you intend to use, and will it be accessible?

 

[Noob2013]

Standard 30A JB amd yes assessing under floorboards.

 

[Pete999]

Standard 30A JB amd yes assessing under floorboards.

Have to check but I don't think under the floor constitutes as accessible.

 

[Noob2013]

30A existing circuit you say ? Is it a BS3036 OCPD ?

Yes correct

 

[Andy78]

Standard 30A JB amd yes assessing under floorboards.

A standard screw terminal JB will not be suitable if under floorboards as this will not be accessible.

 

[Andy78]

Yes correct

Then I suggest you carry out a cable calc for your proposed alterations, assess the current piece of cable for suitability for continued use, and consider the RCD requirements needed for the proposed alteration too.

 

[telectrix]

but if a trapdoor is fitted, with the carpet cut and gripper strip applied around the access point? when will the iet define what is accessible? will this be a new edition, another £75.?

 

[Noob2013]

The 6mm cable tests out fine. Will be used to supply 4 double sockets and a fcu on a kitchen so not a big load.

It's just an alternative to pulling in a new circuit and also prevents the risk of overloading with the house on one ring.

Needs RCD protection.

Can you get a maintenence free JB for 6mm ?

 

[telectrix]

wago do a 6mm 40A connector. it's how you interpret M/F includeing the enclosure.

 

[Noob2013]

wago do a 6mm 40A connector. it's how you interpret M/F includeing the enclosure.

Ideal, just found the wagos.

Wago do the maintenance free JB's but I'm guessing a 6mm and 4mm won't fit easily.

Would you say that this wiring method (with MF JB) is an acceptable alteration?

The only other way other than new circuit or massive alteration is to keep the kitchen on the ring. I'm just concerned about overloading.

 

[hightower]

By my reckoning, with a rewirable fuse the 6mm isn't gonna cut it on a 30A OCPD, let alone a 4mm. You might get away with it on a 20A OCPD depending on your calcs.

 

[Andy78]

Ideal, just found the wagos.

Wago do the maintenance free JB's but I'm guessing a 6mm and 4mm won't fit easily.

Would you say that this wiring method (with MF JB) is an acceptable alteration?

The only other way other than new circuit or massive alteration is to keep the kitchen on the ring. I'm just concerned about overloading.

I would be concerned about the apparent going ahead with this without cable calcs for this alteration. My initial suspicion is that the alteration as you have described will not be suitable or compliant.

 

[7029 dave]

By my reckoning, with a rewirable fuse the 6mm isn't gonna cut it on a 30A OCPD, let alone a 4mm. You might get away with it on a 20A OCPD depending on your calcs.

Take a look at table h2.1 appendix h.

 

[hightower]

Take a look at table h2.1 appendix h.

Sorry, only got red OSG in digital... will check later at home unless you can enlighten me?

 

[hightower]

Ah, is it table 8A in the red OSG, you referring to A1, A2, & A3 circuits?

 

[7029 dave]

Ah, is it table 8A in the red OSG, you referring to A1, A2, & A3 circuits?

Yes indeed.

 

[hightower]

Yes indeed.

Okay, OSG table 7.1 says a 30A circuit in 4mm is not permitted on a BS 3036.

 

[7029 dave]

Okay, OSG table 7.1 says a 30A circuit in 4mm is not permitted on a BS 3036.

I have the green book and it states you can on bs 3036, so I stand corrected.