"It is not permissible to introduce an external connection for the purpose of intentionally creating a residual current to trip an RCD."
What problems, hazard or danger will ignoring this regulation create?
Z.
Zoomup:gkenyon:
Such a current would be applied downstream of the RCD. If the RCD trips, or is used as a point of isolation, and the arrangement tries to apply current, you are left with a current which might have nowhere to go except the person to whom additional protection is being offered, or whom the isolation was intended to protect.Yeh but it is such a tiny current originated through a big, erm, high value resistor.
Z.
I was thinking of using one of Andy's recently recommended under/over voltage monitoring modules configured to be wired in parallel with an R.C.D. test switch. If my whole system was contained in just one enclosure would it comply? Would it be safe?
Z/
I was thinking of using one of Andy's recently recommended under/over voltage monitoring modules configured to be wired in parallel with an R.C.D. test switch. If my whole system was contained in just one enclosure would it comply? Would it be safe?
Zoomup:gkenyon:
Such a current would be applied downstream of the RCD. If the RCD trips, or is used as a point of isolation, and the arrangement tries to apply current, you are left with a current which might have nowhere to go except the person to whom additional protection is being offered, or whom the isolation was intended to protect.Yeh but it is such a tiny current originated through a big, erm, high value resistor.
Z.
It only takes a tiny current ... we are discussing mA. What is the safeguard if the resistor fails?
gkenyon:Zoomup:gkenyon:
Such a current would be applied downstream of the RCD. If the RCD trips, or is used as a point of isolation, and the arrangement tries to apply current, you are left with a current which might have nowhere to go except the person to whom additional protection is being offered, or whom the isolation was intended to protect.Yeh but it is such a tiny current originated through a big, erm, high value resistor.
Z.It only takes a tiny current ... we are discussing mA. What is the safeguard if the resistor fails?
It tends to burn out and go open circuit in my experience of R.C.D. and R.C.B.O. devices.
Z.
Zoomup:gkenyon:Zoomup:gkenyon:
Such a current would be applied downstream of the RCD. If the RCD trips, or is used as a point of isolation, and the arrangement tries to apply current, you are left with a current which might have nowhere to go except the person to whom additional protection is being offered, or whom the isolation was intended to protect.Yeh but it is such a tiny current originated through a big, erm, high value resistor.
Z.It only takes a tiny current ... we are discussing mA. What is the safeguard if the resistor fails?
It tends to burn out and go open circuit in my experience of R.C.D. and R.C.B.O. devices.
Z.
Not all resistor failure are OC - and if the problem with the "external device" is that it may be exposed to an environment, perhaps moisture or humidity, that an RCD is not. Certainly, the "limitation of discharge of energy" option is no longer included in BS 7671, although the concept has not disappeared from product standards - there are two concepts in BS EN 61140 for this: limitation of voltage; and limitation of steady-state touch current and charge.
We should also consider that an RCD is often used for additional protection when other protective measures have failed, so "breaching" and RCD providing additional protection isn't in the spirit of the device.
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