On Nov 18, 8:04*am, "ARWadsworth"
wrote:
R D S wrote:
On 17/11/2011 20:33, A.Lee wrote:
R D *wrote:
On 17/11/2011 19:48, A.Lee wrote:
R D * wrote:
Our landlord has had a consumer unit fitted in place of a fusebox
at the shop we rent.

One of the machines I use, when starting up, is causing a breaker
to trip. The machine contains little more than a big motor.

What current is the appliance rated at, and what current is the
relevant circuit breaker rated at?
It is likely that it is drawing too much current to start up the
motor. A change to a 'C' type MCB may work (usually B type
breakers are fitted, the C allows a bigger current to be drawn for
a short time), or if the cabling allows, a bigger rated breaker.

The machine has a plate on it stating 14 amp. I assume that is the
start up current, I would be very surprised if it drew that while
running. I think the breaker is 16 amp but i'm not 100% (i'm at hone
right
now) that doesn't sound like much.

Electric motors suck up a lot of current to get started, so i
wouldnt be surprised if that is causing the breaker to trip.
A word with the sparky who installed it is my best advice, as he
knows what the cables are etc, and could fit a C type MCB if he
thinks it is suitable.
Alan

The sparky merely scratched his head while the breaker kept tripping
and told my landlord that we had too much equipment and that we were
overloading the circuit. (All of the other equipment was idle)

I unplugged everything else and demonstrated that it was this one
piece of equipment causing the problem. The sparky then said it was
because the machine is old.

I argued that a new machine would work in exactly the same and would
cost £16k so we needed to get it working. It ended up with a
blistering row between my landlord and myself because the sparky has
convinced him that I am somehow using his electrics inappropriately.

Another instance where I am sorry that a 'professional' was involved.

Does not sound like a professional to me.

You are overloading the MCB, however any sparks should be able to work out
of you can safely use a C type breaker on that circuit, or indeed a 20A MCB
or a 20A C type MCB to stop the tripping.

I am afraid that you cannot just swap the MCB to a C type without doing some
measurements which of course the sparky should be able to do - assuming that
he is a sparky and not a drinking pal of the landlords.

If you have access to the installation certificate that was issued with the
CU swap then we can tell you what breaker you can use:-)

--
Adam

Interesting Adam - why can one just not swap to a C type. My previous
circular saw motor tripped the MCB - it was hard wired onto a 20A trip
- so I just changed it for a C type and have had no more problems.

I assume that the measurements you are talking about is some sort of
current/time profile and with all due respect to most sparkies I'm not
sure that they wouldn't know what that even meant.

Rob