Earthing point on an angle-poise infrared heat lamp.

At first, it was just a simple repair job, after a Student had had the good sense to enquire about the safety of the flex going into the plug, because she noticed the inner insulation was just visible. The person being asked did swither about repairing it herself, but then decided it'd be better to ask that engineering tech fella.

Cable clamp in the plug was as it had been at the time of sale, not on the outer insulation, by a fair distance. That should have been picked-up by the portable appliance testing (PAT) contractors over the past two to three years. They couldn't have opened the plug, as it was an obvious fail of the visual inspection.

Shortened the wires, and fitted everything back, properly. Whilst about to fit the cover on the plug, noticed a tiny hairline crack to the Earth pin. "Grrr." Plug taken off. New one fitted. PAT testing time. Visual inspection ok; Earth test... fail. "Eh?" Tried testing to various metal parts. All fail, with the exception of the one little cam shaped piece of plate that the Earth wire was connected to, one of the least likely parts to become live in the event of some sort of cable damage. The most handled part, the lamp and shade, would be a high risk area, as it's moved about every time the lamp's used, and there's heat nearby from the IR bulb. It wasn't earthed at all, and there was no extra insulation between the live and neutral wires and bare brass collar they passed through.

Needless to say, it was condemned at this stage, along with another of the same type.

There's more. No CE marking, nor the newer (since Brexit) UKCA logo, though the latter isn't fully applicable yet on imported goods. There were no compliance logos of any type on it (other than those on the flex).

Could have stopped there, but curiosity got the better of me, and I opened up the little cable-mounted brightness controller for the lamp. Oh dear. They've taken the Earth wire via a printed circuit board, which meant that the cross-sectional area of the copper track was substantially reduced from that of the wire. That area determines how much current can be taken by the wire or track. Because the track was a much smaller area it would be a weak point that would act like a fuse and blow before the wire. Not good. They'd also put a fuse in the neutral wire. No, fuses go in the live wire. A blown fuse in the neutral wire could mean an exposed part could become live... especially if it isn't earthed.

For the other lamp, it's cord grip was also a fail, but not quite as bad as the first, by at least being partially on the outer flex. There was a copper strand not in the Earth connection, and whilst removing the  plug to disable the lamp from being used, the copper strands of the live, neutral and Earth wires that are clamped by screws in the plug, mostly fell apart. A photo I'd taken earlier of the inside of the plug showed that the screw heads had all been slightly chewed-up, probably from being over-tightened with a power tool, which had also chewed up the copper strands. That could have been done in this country. It's likely that the lamp had some other type of mains plug fitted by the manufacturer, and someone else had cut those off and fitted UK type plugs.

Back to the start. Well done to the Student that brought her concerns about the safety of the flex to our attention. I have a fairly substantial report to do regrading this, and portable appliance testing.

So much for that simple repair...