Residual Current Circuit Breaker

Please Don't.

Unless you are a Qualified Electrician, at which point you should not need to ask these questions. Do NOT try and design and install the Main board or anything else electrical in your home.

Get someone with the appropriate training and skills to do it for you.

Your Familys Lives and your own are worth much more to you than any bill you may recieve.

Playing with what is basically your homes safety system is not worth it.

Regards,
Sapper

Thanks for your advice. Definitely I will find a professional person to design it, the question I ask just for my own knowledge. FYI, I am actually a student in Electrical Engineering, I hope I can learn sth from this, hehe...

I hope someone can answer my question. Thanks...

Now there is the best answer yet!

Also please note that the CR4 forum asks you students NOT to try to have the rest of us do your homework for you. How will you ever learn if you cheat?

dear student i would suggest collect manufacturer catalogues like ABB,Merlingerin etc go through the same you would find plenty of educational material to select your information the catalogue should be available free or Else log on to the websites of ABB or Merilyn Gerien you would find the information you are looking for.Good luck

CRM

Its usual practise not to put the lighting circuit on the same RCD as the rest, either no RCD on the lights or a seperate circuit. Reasons - they always seem to trip at night and filament lamps often short to earth when they blow.

Most manufacturers supply boards already split in this way

Hai friend,

In regard to your requirement, please refer some good catalogues by reputed manufacturers. The following points may be kept in mind.

The current rating must account for the starting surges in your system.

The leakag current rating must be selected in regard to your earthing effectiveness and please do keep in mind that wrong selection of this will cause intermittent tripping whcih in your life would be highly unwanted,

As a thumb rule , please select the current rating as 3 times the total rated current. The isolator current can be 50 mA.

Moreover standard manufacturers have the devices with good combination ratings.

REgards

BINNY

Hi there,

If everything is exactly as you described in your request, then it's quite simple:

You can adequately use a 50 A RCCB for that Load together with 50 A isolator. The RCCB sensitivity shoul be 30mA.

Hope you're satisfied.

I do not recommend that you do any electrical design yourself.It is dangerous, as well as illegal in most cases.However, if you would like to see examples of how to calculate loads in various instances, consult the 2008 National Electrical Code HANDBOOK.It is hardback, and has examples and illustrations that are very helpful, whereas the standard NEC codebook does not go into much detail on HOW to do things, it simply states how things should conform to the code.

Good luck in your career.The goal of a school of any kind is to teach a person how to learn, because what you learn today will soon be obsolete, and you must never stop learning in order to succeed.

My understanding is that NEC = National Electric Code but this is a North American term. Does every country refer to their electric code as NEC? For example Canada and the US both have a NEC book. However these two books differ greatly in some details. In Canada the rules are determined by CSA and in the US by UL. Sometimes CSA and UL agree but other times does not.

Example: I was horrified to learn that in Florida it is apparently acceptable to wire both white neutral and green gorund wires to the same common bus bar. This contravenes the Canadian code which require electrical distribution panels to have the neutral bus bar isolated from the steel enclosure.

In Canadian made power panels the white neutral bus bars are insulated from the metal box, but is joined to the ground bus and box enclosure and thus grounded, by a special brass screw. A cardboard note in fastened to this brass screw reminding the installer to remove the screw if the panel is a sub panel rather than the main service entrance panel. Canadian code prohibits having more than one main grounding point for a residence. The ground point must be at the main service entrance.

Mention is made to RCB in the original post. I realize this is common in 230V 50Hz countries. N. American standards usually require individual outlet protection in the form of a GFCI ( ground fault circuit Interruptors). The trip threshold is set at 5 milliamp for 120V. Do all 50Hz countries use a 30ma threshold for the RCB?

\

Elnav,

It's not the 50hz, It's the 230V that sets the 30mA, although for certain commercial applications upto 300mA is available to cater for the issues associated with Switch Mode Power Supplies.

In Australia a 40A\30mA RDC is required at the Point of Supply as a Minimum, anything installed on branch circuits are an optional extra.

Regards,
Sapper.

Re RCDs under yhe new regs 2007 individual rcds are required for each circuit

Which Electrical Authority governs Fiji?

Hi

RCCB is residual current operated circuit breaker with out integral over current protection.

for house hold rather than using RCCB, i advise to use RCBO which is Residual current operated circuit breaker with integral over current protection, the advantage of using this is u need not to pur RCCB and Isolator, RCBO work as RCCB and as isolator too,

only the thing that matter is the Rating of that device, normally any electrical devices are designed to withstand 15 to 20 % more power then its intended rating,

so RCBO of 50A of main current rating and 100 mA of leakage current rating is suitable for your requirements.

Best regards

divyesh patel

Choice of <...RCCB...> is based on a number of factors.

• If the <...house...> is on TN-S or TN-C-S earthing, it probably won't need one. If it is on TT, however, 100mA would be a typical trip setting, selected so that a line-to-earth fault or a neutral-to-earth fault will cause it to trip on imbalance.
• The disconnect rating depends upon the rating of the feeder cable circuit protection device, which might be a 60A, 80A or 100A fuse (UK), among other things. Clearly, the device needs to survive continuous operation and also disconnection at this level of current.

The question that must arise is why there isn't one already. Or, if there is one, why is it deemed worthy of replacement.

In any case, it is recommended that it be selected, installed, tested and certified as safe by a local qualified Electrician.