Bonding of conduit in kitchen floor

[Lagentium]

Bit of a debate today, advice please as regs book not possible to get in my hands until tomorrow. New job, apartments, in the kitchen there are 2 x 25mm conduits from an external wall to an island within the kitchen that is free standing, to be able to get the hob supply across and lighting with a spare in case any sockets are added at a later date. My question is, do these require bonding? Thanks in advance.

 

[Ian1981]

Regulation 412.2.4.1 I feel covers it in conjunction with ref 412.2 so I don’t think it’s a requirement.

 

[Andy78]

There are exceptions to the requirement to Earth exposed-conductive-parts. One of which is where the wiring system is deemed to be double insulated.

Can you point me in the right direction for that ?

 

[Deleted member 26818]

410.3.9.

 

[Andy78]

410.3.9.

Thanks. So 410.3.9 negates 411.3.1.1 as long as 412 is satisfied. Next question for me is does twin and earth satisfy 412 as double insulated ?

 

[Ian1981]

Well it’s deemed to provide satisfactory basic and fault protection as does an item of class 2 equipment.
I’m aware that every one bangs on about twin and earth is not class 2 blah blah but there it is.
Check out guidance note 8

 

[Deleted member 26818]

On second thoughts, I don't think T&E does satisfy the requirement to deemed double insulated.
I believe the CPC has to also be insulated and sheathed to comply.

 

[Andy78]

On second thoughts, I don't think T&E does satisfy the requirement to deemed double insulated.
I believe the CPC has to also be insulated and sheathed to comply.

I've heard that before in respect of bringing cable into class 2 accessories. Flex is acceptable because the cpc is insulated to the same voltage as the live conductors.

 

[Deleted member 26818]

In this instance though, the CPC of the T&E is not exposed within the enclosure.

 

[Ian1981]

The cpc only needs to carry fault current so it’s irrelevant if it’s not sleeved in this case as it’s not classed as a live conductor

 

[Risteard]

Try regulation 412.1.1 double or reinforced insulation
Basic protection and fault protection are provided by reinforced insulation between live parts and accessible parts.
Regulation 412.2.

Singles don’t have reinforced insulation so understandably need containment as per regulation 521.10.1,where as twin and earth does, so I’d say it’s not necessarily a requirement to Earth the conduit if metal containing insulated and sheathed cables

Insulated and sheathed cables do not provide either double or reinforced insulation. They merely provide mechanical protection.

 

[Deleted member 26818]

The requirement now is for any CPC that traverses an enclosure to be insulated as though they were live parts.

 

[Deleted member 26818]

Insulated and sheathed cables do not provide either double or reinforced insulation. They merely provide mechanical protection.

Wiring systems are deemed to be double insulated if adequate mechanical protection of the basic insulation is provided by a non-metallic sheath or non-metallic conduit.

 

[Ian1981]

Wiring systems are deemed to be double insulated if adequate mechanical protection of the basic insulation is provided by a non-metallic sheath or non-metallic conduit.

Yes that’s how I read it sort of
Yet to be convinced otherwise

 

[Ian1981]

Insulated and sheathed cables do not provide either double or reinforced insulation. They merely provide mechanical protection.[/QUOTE I would say that any non metallic sheathed cable whether single core, multi or flat t&e affords protection against basic and fault protection contact much like class 2 equipment but isn't to be regarded as class II in itself.

 

[westward10]

To be double insulated you require two layers of "electrical" insulation or a single layer or more of reinforced insulation.