On Friday, 17 November 2017 11:05:38 UTC, Andy Burns wrote:
whisky-dave wrote:

what makes yuo think it;s 40 amps will you answer this or not.

I do not think your heaters are taking 40A. We were discussing why the
MCB didn't trip, because a 32A breaker can supply more than 40A for
hours without tripping.

only 140 amps where or how did you get that figure ?

You just glibly replied to Johns message where he showed you ... he
wasn't saying your heaters are taking 140A, rather that in the even of a
short circuit (where ideally you'd want many hundreds of amps available
to ensure the MCB trips in under half a second) your 202V supply could
only supply 140A which would take it 20 seconds to trip.

What makes you think it could only supply 140A ?. Isn't that the case with all 32A MCB anywhere in the country so if that is a fault of the MCBs maybe they need redesigning.
Suppose we were drawing 32 amps (4 heaters) what would be the calculations then ?




140A at 202V is 22kW heating up your cabling, your lab should be toasty
until the fire service arrive.

What makes you think that

but it wouldn't be 140A at 202V would it. If we can only get 40A at 202V what makes yuo think we could get 140A at 202V surely as the current increased the voltage between L-N would drop.
It droped from ~215V at 0A to ~202V at 40A, I'm pretty sure that once it got to 50 Amps the voltage would drop below 200V.