Bathroom Supplementary Bonding

[davas]

Hello all,

I need a bit of advice on how I should do the bonding required in my newly fitted bathroom. Below is a picture that will hopefully help explain all the info better than me describing it with words...

A further note is that I intend to box-in all pipework other than those parts that need to be exposed to feed into the various fittings.

I understand from what I've read that any exposed metal parts should be connected together (4mm or 6mm) using earthing cable and clamps to make the path to earth 'equal' for everything connected.

How does this apply in practice - can i do all of the bonding under the floorboards as long as this is accessible? - I do not want a couple of earth clamps hanging from my CH pipes that feed into my nice modern chrome towel rail! The others are not quite so bad...

Any help about where you would bond and what exactly needs to be bonded would be gratefully received.

Thanks in advance

Chris

 

[mikely]

The standard reference for what does and doesn't need bonding: http://www.iee.org/Publish/WireRegs/EarthingPlasticPipes.pdf

plus lots of threads on this forum covering all aspects of supplementary bonding - do a search.

 

[davas]

no points for the pretty picture?

That is a useful document thanks!

does the suggestion below "work"?

specific questions...

The shower is fed from the same cold water feed as the bath and are connected with soldered joints. Do i have to make a connection at the shower unit if the feed goes in through the back of the unit housing.. therefore not an exposed part?

Also my shower pull switch is in Zone 3 as are the spotlights. If i read this correctly then all of these parts should be bonded too?

My spotlights do not have an earth connection/terminal ... how can i possibly earth them? (Pull switch is fairenough!)

 

[JohnD]

Also my shower pull switch is in Zone 3 as are the spotlights. If i read this correctly then all of these parts should be bonded too?

My spotlights do not have an earth connection/terminal ... how can i possibly earth them? (Pull switch is fairenough!)

[/img]

that's not quite how it works... you bond to all the circuits that come into the bathroom. So, the shower circuit, the lighting circuit and (if you have them) the circuit for the electric towel rail, immersion heater and the shaver sockets, if they're not fed from a circuit already bonded.

E.g. if you've bonded to the lighting circuit, you don't have to bond separately to the light switch and each spotlight, because they're all connected to the circuit's earth conductor.

Are you spotlights free of exposed metallic parts?

If you are worried about the earthing connections on the towel rail looking inelegant you are allowed to have them on the other side of the wall they go through. This can be handy if they pass through an airiong cupboard. They have to be accessible for inspection unless e.g. soldered or brazed on.

 

[securespark]

According to NIC snags and solutions, you don't need to bond the body of an electric towel rail, it can be bonded through the cpc.

And don't bond any SELV spotlights!

 

[davas]

that's not quite how it works... you bond to all the circuits that come into the bathroom. So, the shower circuit, the lighting circuit and (if you have them) the circuit for the electric towel rail, immersion heater and the shaver sockets, if they're not fed from a circuit already bonded.

E.g. if you've bonded to the lighting circuit, you don't have to bond separately to the light switch and each spotlight, because they're all connected to the circuit's earth conductor.

Are you spotlights free of exposed metallic parts?

If you are worried about the earthing connections on the towel rail looking inelegant you are allowed to have them on the other side of the wall they go through. This can be handy if they pass through an airiong cupboard. They have to be accessible for inspection unless e.g. soldered or brazed on.

John,

Thanks for trying to explain this...

My spotlights are mains voltage but do not have an earth connection on the fitting themselves. The connection block has a connector for the earth but this does not appear to be connected to the metal casing of the light itself.

The light fittings themselves are not earthed becasue of this so I don't need to worry about bonding them or the light switch (outside the bathroom)?

The shower circuit is earthed directly to the consumer unit... from what i understand i need to bond from the shower circuit to the other metal pipes in the bathroom. Can this not be done at the main earth block next to the consumer unit? (ground floor flat so CU is only about 3-4m away from the shower)

Also... just to clarify my towel rail is not electric... just a standard central heating fed. I'll be OK to bond under the floorboards so long as there is access to them for inspection.?

 

[davas]

According to NIC snags and solutions, you don't need to bond the body of an electric towel rail, it can be bonded through the cpc.

And don't bond any SELV spotlights!

Thanks securespark,

Towel rail is not electrically fed - just CH water pipes and lights are not SELV.

Is it usual for chrome mains spotlights not have an earth connection?