Rcbo ratings

[EpicTone]

Hi,

If I have a 10amp rcbo does that mean I can only have 10amps of lighting load connected to that feed ? 
 

seems like an obvious question but I don’t quite understand.

type c, b, d indicate the fault current tripping point . If it’s only 10 amps why would it need type d for example where they are designed to trip are between 100-200a.

referencing 

electricaapprentice.co.uk/how-do-you-select-the-right-mcb-or-rcbo

 

[Andy™]

inrush currents

 

[Murdoch]

10A of lighting is a hell of a lot of lights IMHO

 

[Sharpend]

10A of lighting is a hell of a lot of lights IMHO

Not uncommon in commercial etc. 

 

[Murdoch]

Not uncommon in commercial etc. 

No but with LED's and in rush tripping must be a huge risk

 

[Bruspark]

Yes you could, but as others have said lighting (even LED lighting) is prone to high inrush currents at the moment of switch on.  Often people get away with it for ages as things are turned on and off at different times etc.   
When a power cut comes at night though all the awitches are left on and when it returns the breaker trips . .   

Not very useful . .

 

[binky]

I looked into inrush currents on LED lighting, they last microseconds, ergo don't last long enough to cause problems, at least not on decent gear. Part of this little job.

 

[ProDave]

I looked into inrush currents on LED lighting, they last microseconds, ergo don't last long enough to cause problems, at least not on decent gear. Part of this little job.

Something I have been asked to "look into"

Customer has just replaced his halogen under kitchen unit lights with LED ones.  the LED ones will do warm white or cool white, and you choose which by turning them on, then off and back on quickly.  Except often when turning them off and back on they trip the B6 MCB.

Apart from telling him he has bought carp lights, what is the most likely solution, swap the B6 for a C6?  Or a B10?

 

[SPECIAL LOCATION]

Something I have been asked to "look into"

Customer has just replaced his halogen under kitchen unit lights with LED ones.  the LED ones will do warm white or cool white, and you choose which by turning them on, then off and back on quickly.  Except often when turning them off and back on they trip the B6 MCB.

Apart from telling him he has bought carp lights, what is the most likely solution, swap the B6 for a C6?  Or a B10?

Obvious questions to ask are....

Are any other lights are on when the tripping occurs?

How big is the existing circuit and what is the current Zs?

i.e. what have you got to play with?

10A 'B'  gives 2.91 less  (7.28-4.37)

6A C  gives 3.64 less (7.28-3.64).

Gut feeling a 10A 'B'  would be my first choice..

AND 

tell them they have bought rubbish lights!!!!!!!!!!!!!!!!!!!!!

Guinness

 

[Phoenix]

Apart from telling him he has bought carp lights, what is the most likely solution, swap the B6 for a C6?  Or a B10?

C6 has IM must be between 30-60A, B10 must have IM between 30-50A . One would be tempted to guess that as long as you meet Zs (3.64 for the C6, 4.36 for the B10, 100% values*)  the C6 might be better if you assume you try and make with the IM middle of the allowed band, but I have a feeling that most makes probably aim for lowish in the allowed range

* from Memory at gone 11, May not be right.....

 

[binky]

Something I have been asked to "look into"

Customer has just replaced his halogen under kitchen unit lights with LED ones.  the LED ones will do warm white or cool white, and you choose which by turning them on, then off and back on quickly.  Except often when turning them off and back on they trip the B6 MCB.

Apart from telling him he has bought carp lights, what is the most likely solution, swap the B6 for a C6?  Or a B10?

Sounds like dodgy light to me. Tell him to pick a colour and stick with it :slap   Think I would head for a C6, otherwise you may affect cabling protection elsewhere in the cct. 

The church is on C curve MCBs, but then that is Philips LED gear - V expensive. It's beem in situ for over 5 years now and is working fine. The tower is liluminated by 4off 300W floods, with  16 off 150W floods doing the rest arranged with a maximum of 5 lights on 1 cct. I can't remember the exact loadings, but I think we kept it below 600W per cct. 

 

[ProDave]

Yes I will measure Zs and see what the circuit can cope with.  But the question was more which would be likely to stand the most inrush current, a C6 or a B10.  And i guess there is no simple answer to that.

 

[Fleeting]

It would be a close call between a type C 6A and a type B 10A on the lower threshold for instantaneous tripping, the type C would be 30A at ×5In, the type B would be 30A at ×3 In. The upper threshold however is different where the type C would be 60A at ×10 In, the type B would be 50A at ×5 In. These are generic figures however and some manufactured tolerances may be tighter. I see plenty of commercial LED lighting happily running on type B 10As but again driver characteristics can play a part. I wouldn't be losing too much sleep over the Zs as the rcbo will provide fault protection and satisfy Regulation 411.4.5.