DIYbanter - Contactum RCBO- am I doing something wrong

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ac1951[_2_]

June 15th 09 11:19 AM

Contactum RCBO- am I doing something wrong

Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

thanks
Andy

Toby	June 15th 09 12:29 PM

Contactum RCBO- am I doing something wrong

stan	June 15th 09 04:54 PM

Contactum RCBO- am I doing something wrong

On Jun 15, 9:29*am, Toby wrote:
ac1951 wrote:
Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

thanks
Andy

The neutral of the circuit should be connected to the neutral output of
the RCBO, NOT the consumer neutral rail directly.

If it is one of thesehttp://www.tlc-direct.co.uk/Images/Products/size_3/CPBR201.JPG

Then if you look at the top of the unit, it appears there is a N Out
terminal on the top somewhere!

Toby...- Hide quoted text -

- Show quoted text -

Assuming RCBO are similar to what here in North America we call
(incorrectly IMO) a GFI they operate to protect the circuit so
equipped when the current through the live and neutral leads differs.
So both the live and neutral leads need to go 'through' the RCD?
Other wise the RCD will operate every time current flows through the
one connected (live) lead?

ARWadsworth

June 15th 09 05:09 PM

Contactum RCBO- am I doing something wrong

"stan" wrote in message
...
On Jun 15, 9:29 am, Toby wrote:
ac1951 wrote:
Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

thanks
Andy

The neutral of the circuit should be connected to the neutral output of
the RCBO, NOT the consumer neutral rail directly.

If it is one of
thesehttp://www.tlc-direct.co.uk/Images/Products/size_3/CPBR201.JPG

Then if you look at the top of the unit, it appears there is a N Out
terminal on the top somewhere!

Toby...- Hide quoted text -

- Show quoted text -

Assuming RCBO are similar to what here in North America we call
(incorrectly IMO) a GFI they operate to protect the circuit so
equipped when the current through the live and neutral leads differs.
So both the live and neutral leads need to go 'through' the RCD?
Other wise the RCD will operate every time current flows through the
one connected (live) lead?

Correct. Andy just had either a blonde/grey moment.

Easliy done.

Adam

Andy Wade

June 16th 09 01:08 AM

Contactum RCBO- am I doing something wrong

stan wrote:

Assuming RCBO are similar to what here in North America we call
(incorrectly IMO) a GFI they operate to protect the circuit so
equipped when the current through the live and neutral leads differs.

To clarify, an RCBO (Residual current Circuit Breaker with Overload) is
the combination of a residual current circuit breaker (RCCB, equivalent
to the North American GFCI) and an MCB. It provides both residual
current *and* overcurrent protection.

When we talk about RCDs on this side of the pond we usually mean RCCBs,
i.e. devices providing only residual current protection and not
overcurrent protection. This is lax use of terminology really, because
'RCD' is a generic term embracing (/inter alia/) both RCCBs and RCBOs.

So both the live and neutral leads need to go 'through' the RCD?
Other wise the RCD will operate every time current flows through the
one connected (live) lead?

Indeed, but you introduce more terminological inexactitude. Formally we
speak of the _Line_ and Neutral conductors, both of which are live (i.e.
current carrying). Use of 'live' to mean 'line' is common parlance
though strictly incorrect. Which interpretation of live is meant is
usually clear from the context though, once you're aware of the scope
for confusion.

--
Andy

John Rumm

June 16th 09 12:02 PM

Contactum RCBO- am I doing something wrong

ac1951 wrote:
Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

This sounds like the area where you probably have the problem.

Both the line and neutral from the circuit need to connect to the RCBO -
note the neutral does not connect to the busbar in the CU. The neutral
wire from the RCBO must in turn connect to the busbar.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

If the RCBO powers up without tripping when no circuit wires are are
connected, and then trips when its test button is pushed, then its
probably ok.

--
Cheers,

John.

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

John Rumm

June 16th 09 12:10 PM

Contactum RCBO- am I doing something wrong

stan wrote:
On Jun 15, 9:29 am, Toby wrote:
ac1951 wrote:
Hi all,
I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.
I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.
However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!
Am I missing something or is the RCBO duff ........
thanks
Andy
The neutral of the circuit should be connected to the neutral output of
the RCBO, NOT the consumer neutral rail directly.

If it is one of thesehttp://www.tlc-direct.co.uk/Images/Products/size_3/CPBR201.JPG

Then if you look at the top of the unit, it appears there is a N Out
terminal on the top somewhere!

Toby...- Hide quoted text -

- Show quoted text -

Assuming RCBO are similar to what here in North America we call
(incorrectly IMO) a GFI they operate to protect the circuit so
equipped when the current through the live and neutral leads differs.
So both the live and neutral leads need to go 'through' the RCD?
Other wise the RCD will operate every time current flows through the
one connected (live) lead?

Yup. Have a look at the last picture ("DIN rail mounting RCBO") in this
section - that is what is being discussed he

http://wiki.diyfaq.org.uk/index.php?...D#Types_of_RCD

--
Cheers,

John.

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

ac1951[_2_]

June 16th 09 01:22 PM

Contactum RCBO- am I doing something wrong

On Jun 16, 12:02*pm, John Rumm wrote:
ac1951 wrote:
Hi all,

I just fitted a Contactum 20A RCBO into a Contactum 17th edition CU.
I installed it on one of the non RCD protected ways.

I have connected the blue wire from the RCBO to the incoming Nuetral
bar and this is also the point where the CCT (being supplied by the
new RCBO) Neutral is connected.

This sounds like the area where you probably have the problem.

Both the line and neutral from the circuit need to connect to the RCBO -
note the neutral does not connect to the busbar in the CU. The neutral
wire from the RCBO must in turn connect to the busbar.

However, as soon as anything is connected to the cct the RCBO trips.
I have moved the cct onto a spare 16A MCB protected by one of the CU's
30mA RCDs and have no problems !!

Am I missing something or is the RCBO duff ........

If the RCBO powers up without tripping when no circuit wires are are
connected, and then trips when its test button is pushed, then its
probably ok.

--
Cheers,

John.

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

Toby, John, thanks for the fedback..

DOH .....
I should have known that but after fitting the RCBO the Neutral cct
connection is hidden at the back of the unit and I then proceeded to
connect the cct Neutral to the Busbar whilst all the time thinking
this doesn't seem right ..

Andy

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