Round-pin sockets

Plus I don't ever remember any suggestion that the radio would only work of the plug was inserted a particular way round, which could cause problems depending on the position of the outlet for the flex.

You definitely would have to connect it the right way round for it to work on DC. They would hardly fit a bridge rectifier. I've seen an AC/DC radio that had an instruction. I forget where, perhaps on the back of the set.

I expect people with DC realised that polarity was important.

Fair comment. I was thinking about AC supply. I am too young to have encountered DC :-) I don't even recall it being spoken about.

Do you know if all DC installations had two pin plugs of if three pins could be used?

Some parts of the town stayed on DC until 1965.

Did all parts of the town start off with DC, if so when did the Volks railway start using the massive ?mercury rectifiers ?.

Volks generated their own electricity, so probably right from the start. It was initially 50v DC, then later 160v DC

So they probably used the rectifiers (or some rectifier) right from 1883.

Why could they not generate DC as I believe Mr Edison did?

You'd have to ask Mr Volk.

It seems that they did. But they were taking a mains supply, so in the

The rectifiers were in use until the 1980s, when they were replaced by solid state equivalents because of the danger from mercury. They were finally removed from site in the 1990s.

Univeral sets used a single valve diode, or occasionally selenium. No-one needs to suggest what is common knowledge.

I used a speaker output transformer to give my dad electric shocks when he fell asleep in the armchair.

No, only the meter was changed.

...and the ORP16

When did an earth become a requirement then? I assume it would be illegal now to install a meter to a property without a working earth. Was there ever a voltage change if (say) the supply voltage was non-standard? Would they change it to 240V AC or keep it as it was? What about appliances?

Yes they are called spring loaded toggle switches.

Even modern light switches have a snap action, it's just not heavy enough to really notice.

Are they an indication that the supply was originally DC or were they used anyway? We had some in our house and I always believed this was because the original supply was with DC from the generating station for the trams.

On a completely different theme, why did they put a fuse on the neutral side (as well as the live)? This would mean if the neutral fuse went, the whole circuit would remain live.

the supply polarity was not guranteed.

I did not realise that. Was this a characteristic of DC only or was there a time when AC polarity could not be guaranteed?

I meant ac specifically, and which pole was grounded