On 28/07/2018 18:09, John Rumm wrote:
On 28/07/2018 14:24, harry wrote:
On Saturday, 28 July 2018 13:28:44 UTC+1, John RummÂ* wrote:
On 28/07/2018 07:46, harry wrote:
On Saturday, 28 July 2018 01:57:48 UTC+1, John RummÂ* wrote:

I wonder how they deal with this in the US (where this style of centre
tapped supply is common), when running 220V appliances that are fed
from
both of the 110V lives? I would expect in this day and age they would
insist on the circuit breaker being a double pole device - but wonder
what they did with fuses?




https://en.wikipedia.org/wiki/Zigzag_transformer

and as usual harry posts a link of absolutely no relevance to the
discussion...

Well ****-fer-brains, zigzag connected transformers were common here
once to supply rectifiers for DC for trolleybuses and trams.

Yup, but irrelevant

The center tapped secondary coils are linked and earthed.

yes

And are still common in the USA

Like I said...

So nothing to do with the question, which for the hard of thinking, was:
what circuit protection arrangements do they use in the US for 220V
circuits wired between two 120V phases, without a neutral?

If Harry were right there'd have been no need for the double pole
breakers in the handful of US apartments we've stayed stayed in over the
years. Or to be more precise, double pole breakers or 2 single pole
breakers with the handles locked together in some circs.

No knowledge of the days of fuses but searching suggests you were right
about fuses on both sides - eg

https://www.nachi.org/bbsystem/viewtopic.php?t=6514

The search also revealed that Adam's cousins seem to have had a very
large slice of the market for pull-out dual fuse carriers for domestic
supplies for a while, something that was news to me:


https://www.google.co.uk/search?q=pull+out+fuse+holder&source=lnms&sa=X&ved =0ahUKEwit4qSAy8LcAhXhJsAKHZh6A0wQ_AUICSgA&biw=192 0&bih=1045&dpr=1

https://en.wikipedia.org/wiki/Wadswo...turing_Company



--
Robin
reply-to address is (intended to be) valid