As per the subject, if one mixes MCBs and/or RCBOs of different makes
in a consumer unit is it likely to stop it conforming to IEE rules?

Also I presume the new (18th edition) rules regarding flammability of
CUs would only apply if one replaces a CU and are not retrospective.
Adding or changing MCBs to RCBOs in an existing CU wouldn't require
that the CU be upgraded to 'non flammable'.

--
Chris Green
·

On 06/05/2019 17:47, Chris Green wrote:

As per the subject, if one mixes MCBs and/or RCBOs of different makes
in a consumer unit is it likely to stop it conforming to IEE rules?

Assuming they are mechanically compatible, then there is no real
practical problem. The resulting setup may not meet type approval any
more, but I can't see that being a issue.

Also I presume the new (18th edition) rules regarding flammability of
CUs would only apply if one replaces a CU and are not retrospective.

Correct.

Adding or changing MCBs to RCBOs in an existing CU wouldn't require
that the CU be upgraded to 'non flammable'.

Yup, if you install a whole new CU then it needs to be to current
standards. No requirement to change what is there.


--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
On 06/05/2019 17:47, Chris Green wrote:

As per the subject, if one mixes MCBs and/or RCBOs of different makes
in a consumer unit is it likely to stop it conforming to IEE rules?

Assuming they are mechanically compatible, then there is no real
practical problem. The resulting setup may not meet type approval any
more, but I can't see that being a issue.

Also I presume the new (18th edition) rules regarding flammability of
CUs would only apply if one replaces a CU and are not retrospective.

Correct.

Adding or changing MCBs to RCBOs in an existing CU wouldn't require
that the CU be upgraded to 'non flammable'.

Yup, if you install a whole new CU then it needs to be to current
standards. No requirement to change what is there.

Thanks John, just what I needed.

--
Chris Green
·

I'd be a little perturbed that CUs were even made that easily caught fire at
any time in history myself. Seems a little counter intuitive to me.
Brian

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"John Rumm" wrote in message
...
On 06/05/2019 17:47, Chris Green wrote:

As per the subject, if one mixes MCBs and/or RCBOs of different makes
in a consumer unit is it likely to stop it conforming to IEE rules?

Assuming they are mechanically compatible, then there is no real practical
problem. The resulting setup may not meet type approval any more, but I
can't see that being a issue.

Also I presume the new (18th edition) rules regarding flammability of
CUs would only apply if one replaces a CU and are not retrospective.

Correct.

Adding or changing MCBs to RCBOs in an existing CU wouldn't require
that the CU be upgraded to 'non flammable'.

Yup, if you install a whole new CU then it needs to be to current
standards. No requirement to change what is there.


--
Cheers,

John.

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

On 07/05/2019 07:52, Brian Gaff wrote:

I'd be a little perturbed that CUs were even made that easily caught fire at
any time in history myself. Seems a little counter intuitive to me.

Its not so much that they catch fire, but more they are unable to
contain one inside the CU. Even plastic CUs are required to be made from
a self extinguishing material.

--
Cheers,

John.

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

On 07/05/2019 07:52, Brian Gaff wrote:
I'd be a little perturbed that CUs were even made that easily caught fire at
any time in history myself. Seems a little counter intuitive to me.
Brian


They don't easily catch fire.
They catch fire more since the requirement to fit active bits like RCDs
as they are more likely to overheat than a plain fuse.

On 07/05/2019 12:43, dennis@home wrote:
On 07/05/2019 07:52, Brian Gaff wrote:
I'd be a little perturbed that CUs were even made that easily caught
fire at
any time in history myself. Seems a little counter intuitive to me.
Â* Brian


They don't easily catch fire.
They catch fire more since the requirement to fit active bits like RCDs
as they are more likely to overheat than a plain fuse.

The cause of catching fire was entirely poor workmanship by electricians
- not doing up the terminal screws tightly enough (or at all in some
cases). It was well researched, because it started becoming a
significant problem in new installations. It wasn't failure or ageing of
any of the internal components.

--
Andrew

On 07/05/2019 21:34, Andrew Gabriel wrote:
On 07/05/2019 12:43, dennis@home wrote:
On 07/05/2019 07:52, Brian Gaff wrote:
I'd be a little perturbed that CUs were even made that easily caught
fire at
any time in history myself. Seems a little counter intuitive to me.
Â* Brian


They don't easily catch fire.
They catch fire more since the requirement to fit active bits like
RCDs as they are more likely to overheat than a plain fuse.

The cause of catching fire was entirely poor workmanship by electricians
- not doing up the terminal screws tightly enough (or at all in some
cases). It was well researched, because it started becoming a
significant problem in new installations. It wasn't failure or ageing of
any of the internal components.


It's now on the 18th edition EICRs that the person doing the testing has
to check the tightness of the bus bar connections and check that the bus
bar to the bottom of the MCBs is actually inside the MCB clamp.

Here is one I found last year.

http://wiki.diyfaq.org.uk/images/8/8d/EICRMCB.jpg

Of course it well worth mentioning that this can only happen with some
CU manufacturers.

--
Adam