Am I missing something obvious here...?

[sythai]

Shower / RCD problem... random tripping when shower is off (shower on it's own CU and RCD - Mira unit only a few months old)

Put my clamp meter on the CPC with shower running 80mA !! RCD not tripping though !! (not fully experienced with my clamp meter just yet only had it a couple of months)

Done a ramp test and trips at 25mA, x1 and x5 all well under

Disconnected tails from shower IR all clear >200.

Going to pick up another RCD to see how that is - crabtree starbreaker RCCB (sure I had problems with these before)

Any thoughts please ?

Thank you

Sy

 

[MarkieSparkie]

Hi Sy, when using your leakage current clamp meter it's better to clamp round the Line and Neutral. Your meter will read the difference between the Line and Neutral currents (i.e. the leakage current), rather than the CPC. If the CPC is clamped you may measure any back feeding leakage from other circuits in addition to the shower final circuit leakage giving an apparently over large leakage current.

 

[oldtimer]

Do you mean a 30mA 80 A RCD also disconnect the shower and test the whole circuit with your RCD tester

 

[Silly Sausage]

Slight addition to Markie's post,
My understanding of RCDs is that they monitor the Line & Neutral currents, if there's an imbalance ie not equal, then the device will trip.

 

[sythai]

Thanks Mark.... will try it that way didn't realise that could be done, couldn't believe it when 80mA showed up !

Oldtimer.... it's an 80a 30mA RCCB, just done the RCD checks with no load connected

 

[londonlec]

Faulty Mira shower. attending two callouts of Mira showers tomorrow

 

[sythai]

Faulty Mira shower. attending two callouts of Mira showers tomorrow

Gonna give the RCD a try first otherwise Mira charge £137 if all ok there end !!