Supplementary Bonding in bathrooms

[binky]

opposite. if there is good continuity, why do you need to improve it

You don't need to improve it.

Likewise as plastic pipe is an insulator especially over 1.5m even if filled with water (a poor conductor) you have to high a resitance to conduct electricity

So to summarise you don't bond for a good conductor, you don't bond for a poor conductor, you don't need to bond if supplementary protection is provided by RCD rated at 30mA on all circuits in the bathroom.

RCD and f*** it ROTFWL ROTFWL ROTFWL

 

[Robojin]

No the plastic piping has to be 1.5mtrs or above.The boffins have calculated that the conductive properties in plastic pipes are equal to the general conductive properties under short runs, but over 1.5 mtrs this conductive propertiy is normally less. If you then bonded the bath for instance you will raise the potential above what would be expected there.

So if tested and you get readings of say 0.001ohms then bond the bath you may get a reading of 0.05ohms raising the potential which would not be required or advised.

Sorry its a little late but I hope I have explained it clear enough.

I thought the book states a run >500mm plastic/water or >900mm plastic/water with inhibitor or are on a different page/reg?

 

[green-hornet]

I thought the book states a run >500mm plastic/water or >900mm plastic/water with inhibitor or are on a different page/reg?

I mentioned the plastic pipe as 1.5 mtrs as this was a figure from my memory as a safe or rule of thumb measurement.

If any one follows any advise given they should if a regulation is quoted check that regulation before doing any work which could be wrong.

However I think I would be right in saying any pipe work in plastic over 1.5 mtrs would not require any supplementary bonding, to a bath or shower.

 

[spinlondon]

You don't need to improve it.So to summarise you don't bond for a good conductor, you don't bond for a poor conductor, you don't need to bond if supplementary protection is provided by RCD rated at 30mA on all circuits in the bathroom.

My understanding, is that supplementary equipotential bonding can be omitted only if 3 criterea are met.

Aditional protection by RCD on every circuit, compliance with Reg. 411.3.2 in respect of disconection times and if all extraneous-conductive-parts have good continuity with the main earth less than 0.05ohms.

 

[binky]

continuity with the main earth less than 0.05ohms.

Copper pipe, soldered joins, main bonds in 10mm - not likely to be a high resistance

 

[Andy™]

Anyone know the CSA of the copper in a 15mm and 22mm pipe?

 

[green-hornet]

Anyone know the CSA of the copper in a 15mm and 22mm pipe?

Could only find the American system which is the American Imperial sizes

http://www.doomlabs.com/science/pipe_specs.html

 

[binky]

Anyone know the CSA of the copper in a 15mm and 22mm pipe?

If you know the wall thickness its a straightforward calculation, base on 1mm wall for 22mm pipe I reckon its about 263mm Sq - but it is getting late, and I've had a long day.

 

[Andy™]

If you know the wall thickness its a straightforward calculation, base on 1mm wall for 22mm pipe I reckon its about 263mm Sq - but it is getting late, and I've had a long day.

your 263mm

 

[Andy™]

You could buy a single surface box, drill out the threads, and then using very long 3.5mm screws screw through the cover plate, through the surface box and into the lugs on the back box.The surface box should cover the back box, as they are about the same size as the cover plates. Some are even a little bigger.

i think your lost.... you want to be here!

 

[spinlondon]

I think you may be right, where's that bloody map?

 

[Andy™]

Cant find the map, so youll have to make do with directions

 

[green-hornet]

In a room containing a bath or shower, additional protection must be provided for all circuits of the location by means of an RCD having the characteristics specified in Regulation 415.1.1 (Regulation 701.411.3.3 refers). It is also required by BS 7671 that the circuit(s) comply with the relevant requirements for automatic disconnection, such that the disconnection times will meet the requirements of Regulation Group 411.3.2, and that extraneous-conductive-parts are connected to the protective equipotential bonding according to Regulation 411.3.1.2.

In such circumstances supplementary bonding may be omitted, as indicated by Regulation 701.415.2.

Regulation 701.415.2 (part of)

Where the location containing a bath or shower is in building with a protective equipotential bonding system in accordance with Regulation 411.3.1.2, supplementary equipotential bonding may be omitted where all of the following conditions are met:

(i) All final circuits of the location comply with the requirements for automatic disconnection according to 411.3.2

(ii) All final circuits of the location have additional protection by means of an RCD in accordance with 701.411.3.3

(iii) All extraneous-conductive-parts of the location are effectively connected to the protective equipotential bonding according to 411.3.1.2.

This was taken from the snags and solutions on this topic of bathroom bonding hope that helps people find the relevant regulations as noted.

 

[binky]

If you know the wall thickness its a straightforward calculation, base on 1mm wall for 22mm pipe I reckon its about 263mm Sq - but it is getting late, and I've had a long day.

OK not right, @31mm Sq based on crbvcurbvubruvbruvbrSQ, and 0.5 mm wall thickness giving internal bore of 19mm on a 20mm pipe. (use diameter for radius last time) Blushing

either way beats 10mm copper, but I admit to having been a bit lack in not testing properly, based on the assumption the connections are good if plumbed in copper with soldered joins, and 6mm shower feed usually gives R1+R2 of around 0.05 to 0.1 in the size of property I normally work in. I shall dig out my wander lead in future.

 

[Andy™]

OK not right, @31mm Sq based on crbvcurbvubruvbruvbrSQ, and 0.5 mm wall thickness giving internal bore of 19mm on a 20mm pipe. (use diameter for radius last time) Blushingeither way beats 10mm copper, but I admit to having been a bit lack in not testing properly, based on the assumption the connections are good if plumbed in copper with soldered joins, and 6mm shower feed usually gives R1+R2 of around 0.05 to 0.1 in the size of property I normally work in. I shall dig out my wander lead in future.

shame the the pipe is 15mm or 22mm!

 

[binky]

shame the the pipe is 15mm or 22mm!

Ok mr pedantic 22mm gives a bigger number and 15mm gives a smaller number - work it out your bleedin self

And NO I'm not doing lead pipes aswell :^O

 

[Andy™]

Ok mr pedantic 22mm gives a bigger number and 15mm gives a smaller number - work it out your bleedin self And NO I'm not doing lead pipes aswell :^O

whilst your at the copper & lead pipes, could always do with CSA of the steel gas pipes, and maybe the new plastic pipes