RCD/MCB/MBN, I need clarification

[mike67]

Hi there!
From my last posting regarding,...63Apms connectors...
At the power source I have a MCB and at the other end I should have some RCD's, question:
I don’t have any 20Amps & 10Amps RCD but only MBN from Hager for the shed CU will this do the job or I have to invest in RCD?

On the RCD, MCB, MBN there are some indications that I am not sure about like: 6000-3 or 3000-3 or 4500-3 is the first number the tripping time of the device in seconds and the 2nd number is it type? If the second is it type, then I am a bit confused, I thought that in domestic system we only use type 1 or B of RCD, MCB, MBN.
Also in a CU do you have to use all the RCD, MCB, MBN of the same type/indications (e.g. only 6000-3 or you can have some 3000-3 with 6000-3 and 4500-3) regardless of the devices’ nominal current which will have to be selected with other considerations?

A single socket that I am going to have designated only for some LV decking lights, output from the plug/transformer less than 1Amps, can I feed this socket from a 10Amps RCB for lights in the shed? So that I could use a 1.5mm2 cable if not I will have to use a 2.5mm cable feed from a 20Amps RCD.

Also these lights are supplied with a plug/transformer; the transformer will be in the shed with its designated socket, can I make this socket “switch able”? From inside the house so that I won’t have to go in the shed to plug/unplug. I know how to do it but I just want to know if for an electrician this is something which is acceptable to do.

Is there any web site where you could check the on-site guide BS7671 online, I don’t want to buy the all book?
thanks for any comments

 

[lettselectrical]

think you'll find the 6000 is the flash rating (short circuit capacity) you need to ideally check the potential fault current on the installation could just be model number as well are they HAGER?.

the socket you could install a 5amp round pin socket as an indication that it is low rated and even label it up 5 amp only.why not install a 5amp switched spur for the decking instead and label this up also as 5 amp or best of all get an etched spur 5amp only that way no one rubbing it off.

as for making the socket "switch able" why not install a switch on the shed supply cable coming from the CU in the house (presuming it on its own dedicated supply).

Obviously with out seeing the actual job these are only ideas and i wouldn't recommend you do any thing unless you are competent and within the law.

 

[333rocky333]

Sometimes the supply to a socket can go via a 20 amp Double Pole switch first, this gives the facility to switch the socket on and off.

You cannot use a normal light switch.

 

[lettselectrical]

TAKE ME OUTSIDE AND SHOOT ME....
am i being stupid???????? sorry i meant to tell you a 20a double pole and not a standard 6amp switch...sorry.
it is late and i have only been home half hour from a long long day.....thats my excuse and i'm sticking to it

 

[Pensdown]

No, your not being stupid. But when you give advice to a DIY'er you have to be very specific. Don't worry, from time to we all get it wrong. You'll soon get the hang of it.

Is that you or your apprentice in your profile pic?

 

[lettselectrical]

neither its the missus.
she keeps hinting she wants to join me in my business......ye right!!!!!! lol

 

[ericmark]

Not a clue what a MBN is? I think everything in Ireland should be RCD protected but this is UK site you would be better posting in “Electrics Outside of the UK” site.
The large number is the PSC (Prospective Short Circuit) current type 1 MCB’s have not been around for some time B, C and D which relates to 5, 10 and 20 times current rating for magnet part of trip. In the UK we are allowed up to 16 amp for lights but most fitting are only rated at 5 amp so normal only 5/6 amp fuse or MCB.
The amps on a RCD refer to what it can carry not what it will trip at it is the milliamps that show what it trips at normally 30ma which should operate in less than 40 milliseconds at 5 times rated current. They are not tested with the button that only checks mechanics there is a special meter to check them with.
The on-site guide and BS 7671 are not permitted to be put on line not sure if you can view in library not even sure if valid in Ireland?
If you were in UK we would be telling you about Part P not a clue if you have any restrictions?
Eric

 

[mike67]

Thanks a lot lad! For your comments

The reason why I am on a UK forum is because Ireland is working with BS which SB is complying with the IEE wiring regulations. so we are talking about the same thing.

About MBN from Hagger, I checked their Web site and for them MCN/MBN/MCB are the same thing (M = miniature; B=breaker, the N I still don't know what it stands for)

For my socket for the decking lights, the power supply is coming from the shed so I will get a separate 5Amps breaker and have the live switched going to the house on a normal switch. (I definitely don't want to have to go outside in the shed to plug and unplug each time I have to use the deck's lights) so why I insist to have a switch in the house.

 

[ban-all-sheds]

About MBN from Hagger, I checked their Web site and for them MCN/MBN/MCB are the same thing (M = miniature; B=breaker, the N I still don't know what it stands for)

No - they aren't "the same thing", except insofar as they are all MCBs.

In "MBN" the B does not stand for "Breaker" it stands for B. And the "M" does not stand for "Miniature".

MBN and MCN are the product codes that Hager use for their range of 6kA MCBs - MBNxxxx are Type B, MCNxxxx are Type C. N appears to be paired with the following digit, and indicates the number of poles, so an MBN1xxx is a single pole Type B, MCN4xxx is a 4-pole Type C

Do you really think you've learned enough yet for it to be safe for you to start installing new circuits outdoors?

For my socket for the decking lights, the power supply is coming from the shed so I will get a separate 5Amps breaker and have the live switched going to the house on a normal switch. (I definitely don't want to have to go outside in the shed to plug and unplug each time I have to use the deck's lights) so why I insist to have a switch in the house.

So why not have the supply for the decking lights come from the house?

 

[ericmark]

OK now I understand a little more there are remote controls for working lights if one was in your shed could you then work it from your house?
Eric

 

[mike67]

Thanks guys,
I appreciate your consideration for the safety side, so far I am only getting information from people whom knows their subject, I won’t get anything started unless all my design are sounded and me happy about the all thing. Usually before I do any jobs of any types, I’ll put it on a drawing and check it 3 to 4 time and don’t let anything to the chance.
I learned a lot since last week and I am still learning today again, I have to be ready for it. (If you have time check out this work I found on the web)
http://www.kevinboone.com/cableselection_web.html

 

[ban-all-sheds]

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[mike67]

thanks B-A-Shed for the links, good stuff

 

[oharaf]

Hi Mike, I share the concerns of the other lads, I really feel you're out of your depth on this one.

Good to find out that BS7671 applies to Eire, I'm toying with moving home myself.

Why not pop in to the Corp and speak to the building control guy and get some face to face advice.

By the way tickets for Croke Park Feb 28th can you get any??????

 

[ban-all-sheds]

Why would a Building Control Officer in the Irish Republic know anything about electrics?