rec.arts.theatre.stagecraft

In article <5kbpabF320jlU1@ >,
"Phil Allison" writes:
>
> "David Lee"
>> John Williamson wrote...
>>
>>> For what it's worth, In Europe, a ground fault protection device *must*
>>> trigger at no more than 30 milliamps after no more than 30 milliseconds.
>>> There are`also rules about regular testing of fixed installations, & for
>>> testing temporary installations before first use.
>>
>> Actually RCDs are available with tripping currents of 10, 30, 100 & 300mA
>> and in time delayed versions. That's only from the MK "Sentry" catalogue -
>> there are probably others available as well.
>>
>
>
> ** Try reading the whole story.
>
> MK state clearly that ONLY the 30mA models are capable of giving good
> shock protection.
>
> The 100 mA models are ONLY intended where a 30 mA one cannot be used -
> presumably because inherent circuit leakage to ground equals or exceeds
> 30mA.
>
> MK also state the a 300mA model is PURELY intended for equipment and fire
> protection.

From the point of view of UK wiring regs, RCDs used for protection
against electrocution must be rated at no more than 30mA (and this
is similar in many other countries wiring codes too).
RCDs for protection against high earth fault loop impedance and
not electrocution should be rated at least 100mA. 300mA and 500mA
are common values too.

10mA RCDs as mentioned above are available but are rare. They are
used for protection against electrocution in restrictive conductive
locations (where someone may not be able to remove themselves from
contact with faulty live part due to working in a location which
restricts movement, such as maintenance work inside a pipeline).
10mA RCDs are also suitable for single appliances, but generally
not suitable for circuits feeding many appliances, particularly
Class I IT equipment.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]