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Old 5th Aug 2020, 5:16 pm   #193
Lucien Nunes
Rest in Peace
 
Join Date: Apr 2008
Location: London, UK.
Posts: 2,508
Default Re: Any other plug collectors out there?

As an aside, the specific compatibility issue here is between installation circuits rated to protect the plug and appliance flex, e.g. the 16A radials popular in mainland Europe, vs. circuits of higher rating that require fused plugs e.g. 32A circuits used in the UK, typified by rings but increasingly these days 32A radials. The radial-vs-ring is a historically related but separate debate.

I took a deep interest in this when the prospect of a new standard resurfaced in the 1980s, that resulted in IEC 60906-1. This rather good but unpopular 3-pin plug, of which 10, 16 and 20A derivatives are used in Brazil and South Africa today, was a potential magic bullet from the IEC that unfortunately missed its target. My approach for retrospective compatibility in the UK was to equip sockets with MCBs in place of switches, so that a standard unfused 16A plug and flex would be protected on a 32A circuit. By protecting a double socket overall at 16A, heavy point loadings on rings could also be avoided. A further advantage was interlocking, whereby the MCB could only be engaged once a correctly-fitting plug was inserted and would trip as soon as an attempt was made to remove it. Yet another advantage was to provide selectable In values for the thermal trip region of the MCB curve when differently-keyed plugs were engaged. If this is beginning to sound like a patent application, I didn't quite get that far! Somewhere I probably still have my mock-ups / prototype.

Anyway, returning to Carnivalpete's observations, this is an interesting viewpoint that adds depth to the situation. However, I do think that compelling suppliers to provide a fitted BS1363 plug (i.e. one suitable for the most widely used socket) was a significant advance. Our legacy of incompatible sockets in the UK had been a lingering excuse to sell appliances with bare-ended flex, resulting in ham-fisted plug-fitting attempts by purchasers.

In the early days of the EAW89 regs and the beginning of widespread periodic ISITEE (aka PAT) I was undertaking surveys of equipment inventories to develop a procedure for testing large local authority sites for the first time. Without a doubt, the most prevalent single defect associated with portable appliances at the time was incorrectly and badly wired plugs, resulting in open-circuit earth connections, imminent short-circuits, exposed live conductors etc. I am of the opinion that had fitted plugs been mandatory for the preceding decade, and in turn had moulded BS1363 plugs been more rapidly adopted, >25% of the hazards identified could have been prevented.

Europlug was a widely-compatible problem solver for using Class II appliances up to 2.5A in any locale with 4-4.8mm pins on 19mm centres. It was designed to be compatible and make satisfactory contact even with 'rogue' and legacy sockets that did not meet current standards anywhere. Had we gone down the IEC 60906-1 route, we could have used them too.That would have avoided the horrendous glut of dangerous unfused, unguarded BS1363-to-19mm centres adaptors that we see today amongst grey imports.

Last edited by Lucien Nunes; 5th Aug 2020 at 5:30 pm.
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