RCD trip times

[Mark.W]

Hi

I have just tested a 80A 30mA time delay RCD model MK 5780s.

The times I get are
1/2x - 2000ms at 0 and 180
1x - 0.0ms at 0 and 46.7ms at 180
5x - 10.4ms at 0 and 6.4ms at 180

These don't seem right because I thought time delay RCD should trip at between 130ms and 500ms at 100%

Could someone please confirm this?

Thanks
Mark

 

[Guest123]

30mA time delayed???

I dont believe there is such a beast???

 

[Mark.W]

sorry i thought it was a time delay because it is a MK 5780s.

 

[Guest123]

I see.

The 's' is a reference to the sentry board into which they fit.

As for the test results it depends on what flavour of tester you have as >2000ms normally indicates a faliure to trip, which it should be at 0.5x the rated current.

The 1x readings are a bit strange but, the 5x readings seem ok.

Was there a lot of electronic equipment in circuit at the time of test??

 

[Mark.W]

Ok thanks for that, makes sense now

Do I need to unplug everything from the circuit, cos I left the fridge, washing machine, kettle etc plugged in and just unplugged the computers, radio and tv.

Thanks for your reply

Mark

 

[Guest123]

If you are getting strange readings then clearing the circuit of all external "noise" would be a step in the right direction.

Dont know which tester you have but the megger stand alone RCD machine is notorious for getting upset with external leakage from appliances and the like.

 

[Mark.W]

Thanks bud

I'll take everything off the circuit and see if it improves, I am using a Fluke 1652

Thanks bud

I just unplugged the lot and got much better readings.

1x at 35.8ms and 62.5ms
5x at 11.0ms and 6.4ms

Cheers