Need to Bond Bathroom

[mt29]

Evening all, i have had a couple of quotes to update electrics in one of my properties, but i am bit confused with bonding of the bathroom.

One quote states i need supplementary bonding to bathroom, but other said there is no need as all circuits will be RCD protected and tested under 1666 ohms????

Is this correct and can i test this myself as i have a multimeter?

Thanks

 

[SparkyNinja]

Can you be a little more specific.

Has an electrician already carried out testing in the bathroom?
In what way did they say 1666ohms?

 

[mt29]

Yes one electrician said he has tested and it falls under 1666 ohms which is the tolerance if RCD protected, but the other electrician said the bathroom still needs bonding?

 

[SparkyNinja]

Well to put it more acuratley:

701.415.2 it states (paraphrased)

No supp bonding required in bathroom if
i) disconnection times met
ii) RCD protection to all circuits
iii) all extraneous conductive parts of the location (ie the bathroom) are effectively connected to main equipot bonding.


So the elctrician who says it doesn't need bonding must also have checked if i) applies, if (s)he did then no bonding will be necessary.


It is likely that the electricians who carrys out a test before they say you need or don't need something done would be the better option IMO.

 

[333rocky333]

all circuits will be RCD protected

Does that include the existing, circuits ie, the light or just the new stuff.

 

[mt29]

Thanks Widdler, i think i will go with this electrician.
333Rocky333 - the new consumer unit will be a split load box with 2 RCD's, so all circuits protected.

Thanks

 

[riveralt]

Yes one electrician said he has tested and it falls under 1666 ohms which is the tolerance if RCD protected, but the other electrician said the bathroom still needs bonding?

These figures quoted apply to TT earthing systems - you will have an earth rod (tape) buried in the garden somewhere - is that what you have?

If this is the case then a figure over 200 ohms is considered unstable.

 

[mt29]

Hi Riveralt, no i don't have an earth rod, my main earth is connected to the supply cable.
He was definitely talking about bathroom bonding.

I am more confuded now?

 

[GaryMo]

I am more confuded now?

Widdlers post above is pretty specific.

 

[ColJack]

These figures quoted apply to TT earthing systems

it applies to TN too if you're using an RCD to meet the disconnection times, but only for circuits not exceeding 32A. ( reg 411.4.9 )

 

[Tipper]

Can someone explain what these abbreviations mean?

TN-C-S
TN-S
TT
PME

Thanks

 

[ColJack]

TN refers to earthing and means Terra - Neutral ( Terra meaning earth.. as in terra firma.. )

TN-S means that the earth and neutral are seperate from the transformer to your house, ie 2 wires.
TN-C means they are combined, ie one wire
TN-C-S means that they are combined to your house and then split up into seperate wires.
PME is Protective Multiple Earthing and is when they put in an earth spike at regular intervals so if the earth breaks somewhere then it's still earthed..
TT means Terra - Terra, when the transformer is earthed but no wire taken to your house, you put your own earth into the ground via a big spike, tape, mesh etc..

 

[ban-all-sheds]

• http://www.tlc-direct.co.uk/Book/5.2.1.htm
  
• //www.diynot.com/wiki/electrics:earthing-arrangements