- Joined
- 27 Jan 2008
- Messages
- 23,801
- Reaction score
- 2,690
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
Had a machine burn out as a result, 110 volt control transformer changed and secondary had internal connection centre tapped to frame, and line 1 was fused but not line 2, so a short on line 2 resulted in complete re-wire being required.One of the problems is people incorrectly use the term 'isolating' when they really mean 'voltage changing'. Typically the yellow 110V transformers fall into this category and of course they are centre tapped to earth.
Many yellow bricks only have overload on supply side, they are often rated 20 amp output rather than 16 amp, common to find 10 amp overload on supply so 10 x 230 = 2300 / 55 = 42 amp to earth, common to find long 1.5 mm² extension leads from the brick, often long enough so a short to earth does not draw 42 amp result in melted cables, one reason why always open both plug and socket to look for damage with PAT test, seen electricians cutting off visible damage in plug and returning to service, to my mind with 110 volt leads sign of melting whole lead cut up and binned.
I would ban yellow bricks if I could, the fire risk with them is far higher than the electric shock risk they remove. Overloads should be on the output not input.