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Old 14th Sep 2012, 4:56 pm   #8
QQVO6/40
Hexode
 
Join Date: May 2009
Location: Newcastle, Australia
Posts: 316
Default Re: Failing Schaffner IEC Inlet Filters

Ref Rifa “X2” capacitors.
Peter “Dinkidi”.
I have to agree with you fully. Only on Monday this week we had an incident at home here with a “Clipsal” branded portable RCD double 15A GPO (general purpose outlet) units. These units have been very popular here in Australia for the protection of tradesmen and other portable appliance users.

I have quite a good workshop and my eldest son was going to do some work outside and as is usual here he grabbed the portable RCD unit along with the electric drill to do his job outside. As a correct procedure he plugged the RCD lead into the GPO in the workshop and switched the supply on. He then did what he should do and he pressed the test button on the rear of the RCD unit to test it’s operation before attempting to plug in the electric drill he was about to use. On pressing the test button, Quite a loud bang, his cry of pain, the workshop power went off, cloud of smoke with a distinct smell and all at once. I grabbed him and thrust his hand into water and then took him to the local hospital for burn treatment.
After making sure he was OK I returned to my workshop to investigate what had occurred with a supposed to be “top class piece of safety equipment”.

The 20Amp breaker in the circuit supply had tripped. The 50Amp 3 phase breaker in the workshop supply board had tripped and the 100Amp 3 phase breaker for the workshop supply in the main property supply board had tripped.

The case of the portable RCD unit was partially melted near a join in the case. Lots of carbon residue around the melted hole. I am guessing that my son was holding the unit in such a way that his hand was somewhere near this burnt hole when it failed. On opening the case of the RCD unit, it was a mess. Melted and burnt plastic. This unit uses an electrically operated solenoid to trip it’s circuit breaker. It has a small printed circuit board in the unit and it seems as if they use an integrated circuit to amplify the signal from the balanced core to sense when there is an imbalance in the incoming and outgoing current to the unit. On the PC board there is a quite large “Rifa” X2 cap. It seems as if this has failed and somehow created an arcing fault.
My son is ok as he had only a couple of hours in the hospital to see the doctor and to get some silver burn ointment along with having to put up with a sore hand for a while. His comment was along the lines of “this equipment is supposed to protect us from injury not to cause it”. I have to agree with him and in this regard I have informed our state government Workcover Inspector of the circumstances of the incident and they look likely to issue a workplace safety alert for these devices. This RCD device was used very often and it still had a catastrophic failure.
So in answer to someone’s comment about “Rifa” cap damage not being so bad I have to disagree. Especially after this last episode of “Rifa” cap failures along with the usual damaged sewing machines, washing machines and numerous other household appliances. I am well and truly sick of the damned things.
I have not yet experienced a Schaffner line filter failure yet but after Peter’s very kind warning I will be on the lookout for them for sure. Remove and execute with large hammer. Hihi.
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