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Hi again JohnW, Your not far from the truth, if you look at your time current characteristics graphs you can see what the cables are capable of coping with. As long as your current carrying capacity is greater than the I2 value of your over-current protective device, your cable will not be...

Westie, For christ sake there are young impressionable minds reading this! I have already spoken about high voltage systems, EEBADS will obviously not work on 11Kv other than for over-current protection at the time of a fault to earth. When you get home, if you intend to prove to yourself...

Hi JohnW, Who told you that? Because I'm afraid it not the truth! The use of a fusing factor will simply allow you to absorb a current spike on start up, when over-current protection is to be supplied by a fuse. If you intend to use a circuit breaker/RCBO to protect a machine with a high...

Hi All, The 're-phrased' question was/is why are we using a fusing factor when calculating the size of circuit breakers and RCBO? Therefore to anybody using fuses and suppling rotating machinery or any machinery with a high starting current, this question obviously is not for you. But this...

Hi Guys, Nice to hear some genuine debate. Westie, For the touching an energised circuit conductor experiment you need to be upstairs with your boots off, standing on floorboards. If you haven't had a nasty shock up to now, it won't be long before you find one! The one thing that you all...

OK, I'll re-phrase the question: Why are we using a fusing factor when calculating the size of circuit breakers and RCBO's?

Ricey, You are giving the impression to the people who have respected your opinions in the past that you are in reality little more than an irresponsible, ignorant, irritating little boy! Is that really what you want people to think of you?

Ricey, You are giving the impression to the people who have respected your opinions in the past that you are in reality little more than an irresponsible, ignorant, irritating little boy! Is that really what you want people to think of you?

Hi All, Why is it that when calculating the size of over-cuurent protective devices we must use a fusing factor, twenty years after we all stopped using fuses?

Hello Mr. Lighting, You evidently haven't been reading this forum lately. The EAWR Regulation 8 and the appropriate definitions are quoted word for word on page 11 of this thread. All you have seen here is a summary; and I'm afraid that is exactly what they say. The Sixteenth Edition of the...

You wouldn't earth the steelwork of a building? This you will have to explain, I could do with a laugh. This arguement that has been going on about earthing for a hundred years was put to bed (for low voltage installations) in 1989 when the EAWR became the Law!

EEBADS is designed to protect members of the public from electric shock with 'low voltage' installations. As far as 'high voltage' installations are concerned insulation and seperation must be the primary means of protection, I don't imagin that earthing can be expected to do any more than...

Ricicle, Be specific and present precise constructive criticism, or don't bother to speak. What ever your name is, If a circuit conductor comes into contact with the earthed steelwork of a building, how is the leaking current returned to the mass of the earth?

"It might disconnect the circuit" simply isn't good enough young man!

Let's start at the beginning with the EAWR: The EAWR only talks in terms of 'conductors' and 'circuit conductors', it tells us that "all conductors (other than 'circuit conductors') must be connected to earth. BS 7671 : 1991 simply expands upon the EAWR, it subdivides 'conductors' into two...

It appears that you need to ask yourselves two simple questions: If an earthed extraneous-conductive-part comes into contact with an energised circuit conductor, will the circuit be disconnected within an acceptable time frame? Would we expect to find any dangerous potential difference between...

ricile, You have circuit protective conductors and supplementary bonding conductors and either or both can be described as earth cables. Circuit protective conductors and supplementary bonding conductors are coordinated in conjunction with overcurrent protective devices a (and/or RCDs') in...

Sparky123, We all need to be very careful because they have used the term 'reasonably foreseeable'. Teenagers take ghetto blasters into the bathroom, women vacuum in the bathroom, this means that extension leads find their way in there (I've even seen somebody with a washing machine in their...

Hi Sparky123, If only half of your sockets are protected by an RCD and you haven't done your supplementary bonding you have the worst of both worlds. If somebody comes into 'direct contact under fault conditions', more than 30mA may be aloud to flow through the victim and if this happens the...

Sparky123, No RCD upstairs? Presumably this means that in your house the RCD is only being used to protect sockets that may supply appliance outdoors, whcih now fails to comply with BS 7671. The EAWR not spplying to DIY in your home home is an interesting point. As an electrician I'm sure...