Any explosion or fire caused by an electrical short circuit or overload (including those resulting from accidental damage to the electrical plant) which either:

1. results in the stoppage of the plant involved for more than 24 hours; or
2. causes a significant risk of death.

i have always taken the view that the term plant in item 1 above refers to the larger operation not the electrical plant. Therefore there can be a short circuit of electrical plant that does not stop the production of the plant ( e.g a solar Park or line in a car factory or an office)

With Chris42

Electrical distribution will occur at several levels - if you merely restrict your definition to the "inbound" supply you miss the nuance of internal control systems and integral safety.

By example, and of necessity, we had two incoming supplies = one was taken off-line for planned transformer maintenance the second was subsequently disrupted by a numpty in the other road with their digger.

We had the "supply" restored quickly (abandoned transformer maintenance) in under two hours HOWEVER we were not able to operate the plant until the back up supply was in full operation some two days later.

It would be poor practice to use the word "plant" twice in the same clause of legislation with a different meaning each time (once to mean an electrical system and once to mean a industrial workplace).

But that doesn't prove anything ...

I hope this explains the RIDDOR requirement as I see it coming from an electrical background.

Firstly I believe that you need to understand the wording of the statement.

IEC Electrotechnical vocabulary.

Short-circuit:    accidental or intentional conductive path between two or more conductive parts forcing the electric potential differences between these conductive parts to be equal or close to zero.

Short-circuit current:    the current flowing at a given point of a network resulting from a short circuit at another point of this network  

Overload:         operating conditions in an electrically undamaged circuit, which cause an overcurrent

BS7671 (Wiring regulations).

No definition of Short-circuit, nor overload

Overcurrent:    A current exceeding the rated value. For conductors the rated value is the current-carrying capacity.

Overload current:         An overcurrent occurring in a circuit which is electrically sound.

Short-circuit current:    An overcurrent resulting from a fault of negligible impedance between live conductors having a difference in potential under normal operating conditions.

So the theme here is that the equipment is inadequate for foreseeable electrical events, ergo, the RIDDOR requirement relates to electrical plant as in switchgear/panels etc.

It also only relates to overload situations or short-circuit conditions.

These scenarios relate to incompetent design (i.e. not adequate for the load – as in an overload current, too many Amps being drawn), or short-circuit between “live” conductors such as a line conductor (phase) to another line or neutral.  Neutral is a live conductor as it carries the same current as the line in normal circumstances.

This clause in RIDDOR relates to breaches of Regulations 5, 7, 9, & 11, of EAWR89.

Therefore it does NOT relate to the wider manufacturing line, complete facility, but the specific item of “electrical switchgear”.  If you look at the wording of these regulations you will see the relevance.

This RIDDOR requirement ONLY relates to overloading, it does NOT relate to an earth fault, unless that earth fault results in overloading of the circuit conductors including the protective conductor.

If the electrical system or plant is designed correctly under the relevant parts of the BS EN 61439 or BS EN 60204 series, then overload under fault conditions, and short circuit conditions must not be possible, thus meeting the requirements of EAWR 5, 7, 9 & 11.

Your only defence would be EAWR 29.

The term “plant” is historical it was used in early editions of the IEE wring rules, and in my experience is still used by the distribution companies (DNO’s) e.g. Western Power Distribution, to refer to their transformers, substations etc.

If I remember correctly it is also used in the Energy Networks Association (ENA)  (the DNO membership organisation for want of a better description) in their documents.

HSE HSR25 the guidance on EAWR tends to reinforce my comments above.