Hi all,

On Friday I will be fitting a new bath which for reasons unrelated to
this thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware that
in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

Now, I'm aware that there is probably more to the 17th Edition than
simply sticking some RCBOs in my CU, but I was wondering if that would
be enough to nagate the need for me to install equipotential bonding.

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting circuits
on the RCD side, but what if I replced them with RCBOs? Would this be
enough to not require equipotential bonding as there would be no
circuits in the house without RCD protection.

Any thoughts/opinions welcomed.

Thanks,
Richard.

"Richard Conway" wrote in message
...

Hi all,

On Friday I will be fitting a new bath which for reasons unrelated to this
thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware that
in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th edition
regs.

Now, I'm aware that there is probably more to the 17th Edition than simply
sticking some RCBOs in my CU, but I was wondering if that would be enough
to nagate the need for me to install equipotential bonding.

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting circuits
on the RCD side, but what if I replced them with RCBOs? Would this be
enough to not require equipotential bonding as there would be no circuits
in the house without RCD protection.

Any thoughts/opinions welcomed.

Thanks,
Richard.

If you are installing a bath and not touching the electrics then there is no
*requirement* to add supplementary equipotential bonding.

If you are also modifying electrics then the modifications will have to be
to the 17th edition (which requires rcds in bathrooms); there is no option
to do it to 16th standards instead, assuming this has not being in progress
for a few years. But even so, it is unlikely that a steel bath would need
to be bonded as it is unlikely to be an extraneous conductive part. The
water pipes supplying it or waste away from it if either are metal might be
extraneous and need bonding.

Why do you think it needs to be bonded?

Regards
Bruce

Richard Conway wrote:

On Friday I will be fitting a new bath which for reasons unrelated to
this thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware that
in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

A new metal bath in unlikely to make the situation worse...

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting circuits
on the RCD side, but what if I replced them with RCBOs? Would this be
enough to not require equipotential bonding as there would be no
circuits in the house without RCD protection.

As long as you main equipotential bonding is up to scratch then you
could replace the lighting MCB with a 30mA/6A trip RCBO. (I am presuming
the downstairs lighting circuit does not enter the bathroom).


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

BruceB wrote:
"Richard Conway" wrote in message
...
Hi all,

On Friday I will be fitting a new bath which for reasons unrelated to this
thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware that
in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th edition
regs.

Now, I'm aware that there is probably more to the 17th Edition than simply
sticking some RCBOs in my CU, but I was wondering if that would be enough
to nagate the need for me to install equipotential bonding.

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting circuits
on the RCD side, but what if I replced them with RCBOs? Would this be
enough to not require equipotential bonding as there would be no circuits
in the house without RCD protection.

Any thoughts/opinions welcomed.

Thanks,
Richard.

If you are installing a bath and not touching the electrics then there is no
*requirement* to add supplementary equipotential bonding.

If you are also modifying electrics then the modifications will have to be
to the 17th edition (which requires rcds in bathrooms); there is no option
to do it to 16th standards instead, assuming this has not being in progress
for a few years. But even so, it is unlikely that a steel bath would need
to be bonded as it is unlikely to be an extraneous conductive part. The
water pipes supplying it or waste away from it if either are metal might be
extraneous and need bonding.

Why do you think it needs to be bonded?

Regards
Bruce



The packaging the bath came in had several largely printed warnings that
it must be earthed.

John Rumm wrote:
Richard Conway wrote:

On Friday I will be fitting a new bath which for reasons unrelated to
this thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware
that in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

A new metal bath in unlikely to make the situation worse...

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting
circuits on the RCD side, but what if I replced them with RCBOs?
Would this be enough to not require equipotential bonding as there
would be no circuits in the house without RCD protection.

As long as you main equipotential bonding is up to scratch then you
could replace the lighting MCB with a 30mA/6A trip RCBO. (I am presuming
the downstairs lighting circuit does not enter the bathroom).


The downstairs lighting circuit does not enter the bathroom, but it does
travel in proximity to the pipework in some places, which I thought
was one of the reasons behind equipotential bonding in the bathroom -
i.e. to prevent a large potential difference occuring if, say, a tap
were to become live as a result of it's supplying pipework coming into
contact with a faulty cable etc.

Our bathroom currently has no equipotential bonding, and I am aware
that in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

..
there should be a bonding wire onto the plumbing somewhere,
i think there's a problem when some of the metal pipe is replaced with
plastic,
so the bonding doesnt reach the bath..

[g]

"Richard Conway" wrote in message
...


Why do you think it needs to be bonded?


The packaging the bath came in had several largely printed warnings that
it must be earthed.

Good answer!
But I would not consider a bath manufacturer as definitive on electrical
matters!

I have re-read 701.415.2.
There is no specific requirement for a metal bath to have supplementary
equipotential bonding.
But if it was an extraneous conductive part it would need to be bonded.
Metallic pipes coming into the location need to be bonded if they are
extraneous.

But the regulation goes on to say supplementary equipotential bonding can be
omitted provided a number of conditions are met:
- main protective equipotential bonding is in place (ie water, gas etc)
- all final circuits in bathroom meet appropriate disconnection times
- all final circuits in bathroom have rcd protection

(I have simplified a bit)

If you are not altering the electrics then my inclination would be not to
start adding new bonding.

Regards
Bruce

Richard Conway wrote:

John Rumm wrote:
Richard Conway wrote:

On Friday I will be fitting a new bath which for reasons unrelated to
this thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware
that in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

A new metal bath in unlikely to make the situation worse...

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting
circuits on the RCD side, but what if I replced them with RCBOs?
Would this be enough to not require equipotential bonding as there
would be no circuits in the house without RCD protection.

As long as you main equipotential bonding is up to scratch then you
could replace the lighting MCB with a 30mA/6A trip RCBO. (I am
presuming the downstairs lighting circuit does not enter the bathroom).


The downstairs lighting circuit does not enter the bathroom, but it does
travel in proximity to the pipework in some places, which I thought was
one of the reasons behind equipotential bonding in the bathroom - i.e.
to prevent a large potential difference occuring if, say, a tap were to
become live as a result of it's supplying pipework coming into contact
with a faulty cable etc.

The bonding is intended to limit the potential difference you can
experience as a result of conductive components introducing dangerous
voltages into the zone. Normally one would only include the CPCs of a
circuit that actually enters the bathroom within the bonding.

However, if you think the layout of the pipework/wiring is such that
there would be a real possibility of the pipework making contact with
the downstairs lighting circuit, then you would be better off installing
supplementary bonding in the bathroom. (in reality the main bonding
would hopefully ensure that the existing MCB on the downstairs lighting
circuit would open should such a fault occur)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

george (dicegeorge) wrote:


Our bathroom currently has no equipotential bonding, and I am aware
that in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

.
there should be a bonding wire onto the plumbing somewhere,
i think there's a problem when some of the metal pipe is replaced with
plastic,
so the bonding doesnt reach the bath..

There is no requirement to bond the bath since it can't by itself bring
a voltage into the zone. Typically the pipes feeding the taps, the waste
connection (if metal), basin taps, CH pipework, and the CPCs of any
circuits used in the room would be bonded.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Richard Conway wrote:

On Friday I will be fitting a new bath which for reasons unrelated to
this thread (well, not entirely I suppose) will be made of steel.

Our bathroom currently has no equipotential bonding, and I am aware
that in order to comply with the regs I will either need to install
equipotential bonding or upgrade my installation to meet the 17th
edition regs.

A new metal bath in unlikely to make the situation worse...

At the moment, my CU is a split load that consists of the following
(please bear in mind it's a small terraced house):

RCD Side
Whole house sockets (ring)
Kitchen Sockets (ring)
Oven (radial)
Immersion Heater (radial)

Non-RCD side
Upstairs lighting (including bathroom fan)
Downstairs lighting

Now, I understand the dangers of putting either of the lighting
circuits on the RCD side, but what if I replced them with RCBOs?
Would this be enough to not require equipotential bonding as there
would be no circuits in the house without RCD protection.

As long as you main equipotential bonding is up to scratch then you
could replace the lighting MCB with a 30mA/6A trip RCBO. (I am presuming
the downstairs lighting circuit does not enter the bathroom).



The main bonding is another issue I've meant to ask about in the past.
The incoming gas pipework is connected just after the meter, but the
water supply pipework isn't connected at all - this appears to be
because the pipework immediately before and after the stopcock is
plastic and goes all the way up to the loft to serve the header tanks.
The original copper pipework is then T'd off this plastic and comes back
down to serve the bathroom/kitchen.

The most sensible way I can see of bonding this would be in the loft -
but that isn't really feasible as there's no easy route back to the meter.

Any thoughts?

Richard Conway wrote:

The packaging the bath came in had several largely printed warnings that
it must be earthed.

Two points: Firstly the rules regarding bonding of baths (and metal
shower trays) have changed. The 16th edition used to list them as
something requiring bonding (this I expect was actually in error since a
bath, can't bring a potential into a zone). The 17th edition has removed
this anomaly.

Secondly, the requirement that existed previously was for supplementary
equipotential bonding and NOT earthing[1].

So the instructions from the bath manufacturer are not only out of date
but at best were sloppily worded.


[1] The purposes of which, and the function of each are different:

http://wiki.diyfaq.org.uk/index.php?...ng_and_Bonding

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/