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Old 25th Sep 2018, 11:33 pm   #33
McMurdo
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Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,263
Default Re: Transformer safety?

I don't think the un-earthed construction of transformer sets would have been cavalier at the time, they weren't meant to be held or transported while in use (unlike say a power tool, which were some of the first appliances to include an earth wire). The earth terminal was supposed to be earthed 'somehow' albeit for signal purposes, whether onto a water or gas pipe, nearby radiator or one of those chemical earths you were supposed to keep watered. Even pre-war sets would've been flash-tested on the production line several times before despatch. There's a video or two on youtube showing a uk radio factory production line in the 30's.

Since transformers insulated with paper and wax could suffer leakage 60 years on, I usually earth mine with a new 3-core flex, since we have the luxury of earthed mains sockets. Such sets of course will also have protruding chassis bolts, an external aerial wire and generally less care to prevent contact with the chassis. That said, I've never had one leak to earth, but there's always a first time.
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