Inside the plug, and fuse ratingsWhy should the earth pin never be sleeved?

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Inside the plug

A good chunk of PAT is opening a plug and knowing what "right" looks like.

Check	Requirement
The plug	Manufactured to BS 1363
The fuse	BS 1362 — a proper cartridge fuse, correctly rated
Pin sleeving	Line and neutral pins sleeved. The earth pin is not sleeved
Cord grip	Gripping the sheath, not the individual conductors
Terminations	Right conductor in the right terminal, tight, no excessive copper showing
Earth	Connected — not floating loose in the plug

✋A sleeved earth pin is a red flag. If you see insulation on the earth pin, the plug hasn't been made to the British Standard — it may be counterfeit. Remove that item from service immediately, whether or not it works.

The cardboard tag is not a fail. That little card inside the plug showing which conductor goes where can just be pulled out and binned. Don't fail an appliance over it.

And never fix a fuse. Bridging a rewireable fuse with foil at each end, for example, is genuinely dangerous, and exactly what this work exists to catch.

Appendix 6 · plug checks BS 1363 plug · BS 1362 fuse

Fuse ratings

The Code of Practice does not pick a fuse from the appliance’s wattage. Two checks, in this order:

1. The fuse the manufacturer recommends (p.79). The instructions or rating plate usually state the fuse rating and the cable size, and specialised equipment such as computers and laptop chargers often specifies something you would not guess.

2. Then check the fuse against the flex. The fuse protects the flex. Table 10.6 gives the maximum fuse by cable CSA for BS 1363 plugs. 0.75 mm² can take a 13 A fuse in a non-rewireable (moulded) plug — but not on a portable socket-outlet — and rewireable plugs have their own, lower limits at the smaller sizes, so read across the right column. 1.25 and 1.5 mm² take 13 A. Older equipment may not match the current table; check the manufacturer’s instructions (10.14.1).

Section 10 · fuse as the manufacturer recommends · p.79 Table 10.6 · fuse against cable CSA · p.80

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18th Edition
Building Regs
PAT
Fundamental Inspection & Testing
Initial Verification
Periodic Inspection & Testing

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