OK, this will not be sorted in one message.
I’ll work backward.
Chris42,
An RCD is a Residual Current Device, this “measures” the current flowing “down” the line conductor “into” the installation, and compares that with what “leaves” the installation down the neutral conductor.
Any difference between the two, must have gone elsewhere, i.e. have leaked to earth, thus earth leakage.
An ELCB is an Earth Leakage Circuit Breaker, this does the same thing.
However, there is an old type voltage operated earth leakage circuit breaker, known as a VOELB, Voltage Operated Earth Leakage Circuit Breaker.
A VOELB, is not considered acceptable for additional protection under current BS7671 (etc.) thinking.
However, any correctly functional, and suitably selected and installed current operated device, no matter how old, and what it’s called is still acceptable for additional protection.
Imwaldra has a point.
CdC,
Who owns the building?
Who is your management company I don’t need names, I just need to know that they are competent to undertake design, construction, inspection and testing of the fixed electrical installation to BS7671, and utilise competent operatives to do this work, and, that the installation actually DOES comply with BS7671. If this is the case then the installation must by default be fundamentally safe, and thus compliant with EAWR89 along with BS7671, and actually be safe, by default.
Your US manager, is not familiar with our installations in the UK I suspect.
In the US they design and install to the NEC, National Electrical Code.
The fundamental ideas of protection under the NEC are different to those under EN 60364/BS7671, ours are IMHO much safer.
IF the installation is correctly designed, constructed and verified as compliant with BS7671, then by the time he even knows that someone is receiving an electric shock, then the system will have automatically taken care of that and disconnected the circuit.
Under BS7671 the way circuits are designed they will disconnect within the designated time thus protecting the individual such that the shock risk is prevented before it occurs, the same with the fire risk.
Our circuit protection (MCB’s) under ISO (EN/BS) standards are fundamentally different to those used under the NEC.
Your idea of in the event of a fire, get out and get the brigade out is totally correct.
There is no way that he can isolate a supply to prevent electrocution, by the time he (anyone) realises someone is being electrocuted, they are dead.
Receiving an electric shock is something totally different.
Under BS7671 it is impossible for anyone to receive an electric shock from a correctly designed, constructed and verified installation.
Next, our protection system under BS7671 is Automatic Disconnection of Supply (AKA, ADS is often noted on the paperwork), this ensures that the supply to a circuit is disconnected in the event of a potentially dangerous fault of almost any kind within a maximum of 5 seconds, which is not for protection of life but property.
So, any correctly designed, constructed and verified installation to BS7671 must disconnect supply in the event of ANY fault in a maximum of 5 seconds, this is inadequate to generate sufficient energy to cause a fire.
There is also an additional protection measure which used to be recorded, but is no longer, but, is still utilised which is creation of an Earthed Equipotentially Bonded zone (EEB, which in conjunction with ADS used to be recorded as EEBADS).
This ensures that all metalwork in the installation which could potentially become live under fault conditions is robustly connected to the building earthing system to ensure that it would generate a fault sufficient to cause ADS in <5s.
Most faults require ADS in much less than 5s, however, I’m not going into detail, and 5s is the MAXIMUM time for ADS.
Now a lot of distribution boards meet the requirements of EN60439-3 & moving forward EN61439-3 which means that they are safe for use by “ordinary” persons.
That is persons with no electrical training or competence.
However, this relies on the labelling and information on the installation being correct and adequate, we are back to your management (maintenance) company FULLY complying with BS7671.
Few do, they hope to but, often pay peanuts and get monkeys.
Up until the 1/7/15 there was no requirement for all circuits to be protected by RCD’s, there still is not, however, all socket outlets up to 20A rated must now be on RCD’s on installations DESIGNED AFTER 1/7/15.
Lighting and other circuits do not HAVE to be on RCD’s and there is no reason for this to happen in a “business” environment, as EAWR requires that all those working on the electrical installation are competent.
BS7671 covers the safety of such circuits to ensure that they cannot cause fires and electric shocks to users of the circuits.
Thus the danger only lie with socket outlets, as the “use” of these is somewhat “uncontrollable”.
However, in a “business” EAWR requires that all persons “using” the electrical installation are suitably competent to do so.
This does not require them to be electrically qualified, but, it does require them to be adequately instructed and supervised, e.g. inducted and managed such that they do not introduce, nor use electrically dangerous equipment within the installation.
“PAT” is a way of ensuring that the “employers” equipment is safe, personal electrical equipment must either be subject to company “PAT”, or otherwise proved safe, or else banned.
This will do for now, digest this and come back, then I will carry on.