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Old 20th Jun 2021, 4:32 pm   #65
ms660
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Join Date: Apr 2011
Location: Cornwall, UK.
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Default Re: Vintage Sears Silvertone radio safety question

Quote:
Originally Posted by sweepthedog View Post
Does that mean it is a shock hazard?
With respect to Earth there's always a shock risk with AC/DC/Live chassis receivers, the only way to reduce the risk to a minimum (apart from not using it at all) is to power the receiver via a proper mains isolating transformer designed for the purpose.

For instance, say a Live chassis design receiver had the mains Neutral connected to the chassis via a single pole on/off switch that was connected to mains Neutral or via one pole of a double pole on/off switch that was connected to mains Neutral and that the Neutral wire in the mains plug was connected to the Neutral pin and that your mains outlet socket was wired correctly you might think no problem at all......think again....if the Neutral circuit was suddenly interrupted for whatever reason the chassis would suddenly rise to a potential with respect to Earth that equals the mains voltage, that's because the chassis would then be connected to mains Live via the low impedance series heater circuit, such an interruption could be caused due to various reasons (not all listed here) such as an intermittent wire or terminal connection, plug to socket connection, and if the Neutral circuit was fused in the receiver then also a poor fuse holder connection or a tired fuse etc.

Lawrence.
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