RCD question

Callumi565 · Jun 27, 2015

Can anyone tell me what thelowest insulation resistance for a low voltage circuit tripping time on a rcd or where i could find this on the regs

andyb · Jun 27, 2015

Well if it's minimum insulation resistance you're after then the reg's will tell you that, table 61.
If however you're after the insulation resistance that will allow 30ma to flow at 230v then you need ohms law.

Callumi565 · Jun 27, 2015

I only have a on site regs in that table in there

Pete999 · Jun 27, 2015

Callumi565 said:
I only have a on site regs in that table in there

Why haven't you got a copy of BS7671? must have for an Electrician I would have thought.

Darkwood · Jun 27, 2015

Callumi565 said:
Can anyone tell me what thelowest insulation resistance for a low voltage circuit tripping time on a rcd or where i could find this on the regs

The regulations will not answer this question they will tell you minimum values that are acceptable. As others have implied, this is a maths question using so if your going to calculate it I would use 20mA as a possible tripping value than apply ohms law to get your answer.