- Thread starter zardoz
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^neo^
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One is a Mini circuit breaker (MCB - like a fuse basically) and the other is a residual current something or other - basically the juice going into the circuit and the juice coming out and if there is a difference (ie a short circuit) it trips.
well, thats what i make of them anyway!
well, thats what i make of them anyway!
malcolm
& Clementine the Cat
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Pretty well that:
MCB is a Miniature Circuit Breaker. It will trip if the current is higher than the current marked on the breaker.
RCD is a Residual Current Device. It compares the current going down the live to the current coming back up the neutral. If there's a difference then it assumes the current is going through you to ground and breaks the circuit.
MCB is a Miniature Circuit Breaker. It will trip if the current is higher than the current marked on the breaker.
RCD is a Residual Current Device. It compares the current going down the live to the current coming back up the neutral. If there's a difference then it assumes the current is going through you to ground and breaks the circuit.
Hello all,
the other slightly confusing thing is that an RCD, although having a current rating does not give overcurrent protection so also needs an MCB to give that. Basically an RCD protects the user and an MCB protects the installation.
There is another device which combines both called an RCBO but they are relatively expensive.
Alec
the other slightly confusing thing is that an RCD, although having a current rating does not give overcurrent protection so also needs an MCB to give that. Basically an RCD protects the user and an MCB protects the installation.
There is another device which combines both called an RCBO but they are relatively expensive.
Alec
Hello Gavuk\LeeW,
the term has changed over the years (as has the way in which they operate) from earth leakage circuit breaker to residual current circuit breaker to residual current device.
I don'r think that an RCCD is the same as an RCBO nor do I know what the extra C is for however?
Alec
the term has changed over the years (as has the way in which they operate) from earth leakage circuit breaker to residual current circuit breaker to residual current device.
I don'r think that an RCCD is the same as an RCBO nor do I know what the extra C is for however?
Alec
gavuk
artful-bodger
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mine wasn't a typo rccb! 40a 30ma,looks like an mcb but has a test button !30ma suggests rcd,40a suggests overload?....its on the feed to my garage,and its been suggested that i fit an mcb for overload protection and is fed from tails off incoming supply...
Jaeger_S2k
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{5.3} has stressed that the standard method of protection is to make sure that an earth fault results in a fault current high enough to operate the protective device quickly so that fatal shock is prevented. However, there are cases where the impedance of the earth-fault loop, or the impedance of the fault itself, are too high to enable enough fault current to flow. In such a case, either:
1. - current will continue to flow to earth, perhaps generating enough heat to start a fire, or
2. - metalwork which is open to touch may be at a high potential relative to earth, resulting in severe shock danger.
Either or both of these possibilities can be removed by the installation of a residual current device (RCD).
In recent years there has been an enormous increase in the use of initials for residual current devices of all kinds. The following list, which is not exhaustive, may be helpful to readers:
RCD residual current device
RCCD residual current operated circuit breaker
SRCD socket outlet incorporating an RCD
PRCD portable RCD, usually an RCD incorporated into a plug
RCBO an RCCD which includes overcurrent protection
SRCBO a socket outlet incorporating an RCBO
Have a look here for more, it's a little dated but still informative?
1. - current will continue to flow to earth, perhaps generating enough heat to start a fire, or
2. - metalwork which is open to touch may be at a high potential relative to earth, resulting in severe shock danger.
Either or both of these possibilities can be removed by the installation of a residual current device (RCD).
In recent years there has been an enormous increase in the use of initials for residual current devices of all kinds. The following list, which is not exhaustive, may be helpful to readers:
RCD residual current device
RCCD residual current operated circuit breaker
SRCD socket outlet incorporating an RCD
PRCD portable RCD, usually an RCD incorporated into a plug
RCBO an RCCD which includes overcurrent protection
SRCBO a socket outlet incorporating an RCBO
Have a look here for more, it's a little dated but still informative?
Jaeger_S2k
Forum Supporter
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- Highfurlong, Blackpool. Lancashire
Sparks that fitted it thought it was ok for job ,other spark thinks it needs mcb to comply with part p ,,,,more research needed me thinks .lol.cheers for replies though.......where is that odd canoeist when u need him
Did he mention which part of Part P he was referring to, or was he just another electrician who doesn't understand Part P and quoted it as it's all they talk about in the brew room?
Residual Current Circuit Breakers
Merlin Gerin has a comprehensive range of Residual Current Circuit Breakers (RCCB) for use in all applications, they are available in various types for general distribution and specific loads. Mounted as incomers for distribution boards or for individual outgoing circuits and for personnel or fire protection. The protection is also available in a range of RCBO products.
AC Class RCCB
For general distribution in lighting and power circuit or applications with mixed loads...
A Class RCCB
Use in commercial applications where equipment like fans, pumps and induction cookers are present...
Si Type RCCB
Use where there is a high risk of disturbance from lightning strokes, electronic ballasts, switching surges...
SiE Type RCCB
As the Si type but with additional environmental protection for installations in aggressive and corrosive areas, marinas swimming pools....
B Type RCCB
Use to provide protection for variable speed drives, battery chargers and inverters...
RED Type RCCB
Use in remote or unmanned application for automatic restoration of the supply following a transient fault...
If you would like a copy of Part P (which is part of The Building Regulations 2000 - Electrical Safety - Dwellings, and not a Marketing Brochure for Electricians). Drop me a PM and I'll send you the PDF Downloaded version.
