Help with new socket installation in Garage.

[andrewsbabu]

Hello every one

I hired a BT engineer to install a 20A power socket in the garage to run a table saw that needs 16A power supply. After installation of the20A type B MCB, it trips when the saw is started. The saw has a 3 hp motor.

The engineer has gone away and will contact me later. Can anyone help/advice as to what could be the problem.

Many thanks
Andrew.

 

[gutterball]

why did you hire a BT engineer to do an electricians job?

 

[daniel hill]

i didnt no you could get a 20A phone socket?
you learn something every day
mcb needs to be motor rated Type C
i bet its only a Type B

 

[Amp David]

Can anyone help/advice as to what could be the problem.

Many thanks
Andrew.

Your problem lies in the fact You hired a BT engineer to do the work for you. Don't they have electricians round your way or something?

 

[daniel hill]

they must have electricians i no that in the street exchanges they have heaters and sockets in them

 

[Richard]

i didnt no you could get a 20A phone socket?
you learn something every day
mcb needs to be motor rated Type C
i bet its only a Type B

What he said.

 

[SKY]

basically when your appliance starts up it pulls more current to get it going than it does in normal operation.
As above for this you need to install a C20 MCB, the "C" denotes that the MCB will tolerate higher currents to get over the start up spike but would trip for prolonged exposure to current over its rated capacity.

LOL - Ask the BT engineer if he also does boilers?

 

[SKY]

they must have electricians i no that in the street exchanges they have heaters and sockets in them

If so he will have known that a C breaker is required once he realised what his customer spec was
If this was a new circuit did he also give you the certificates required to meet the requirements of the law?

 

[Mark_Burgess]

I am with Sky, what certificate did you get?

 

[jaresquire]

C'mon guys, you never fitted a BT point?

 

[derek preece]

Bt points do not have 230 volts and perhaps 200 amps of fault current

 

[jaresquire]

Thats where I'm going wrong then!

 

[Amp David]

C'mon guys, you never fitted a BT point?

Many times but mever tripped when I started up any power tools

 

[cdavies33]

loving all this banter, haha!

 

[andrewsbabu]

Thanks guys, some of you have answered my question. The guy who came over is a qualified electrician.

 

[tlangdon12]

While the Type B/C MCB mixup is probably the cause, is there not also a risk that the MCB is tripping because of a fault?

Could the electricians on the forum indicate what tests the BT Engineer should carry out to determine that the motor and its connection is not faulty?

 

[derek preece]

I'm not being funny but i thought that the 'BT engineer' is also an electrician. The standard tests should have already been done, R1+R2, insulation resistance, Ze, polarity etc.

 

[Paul.M]

i didnt no you could get a 20A phone socket?
you learn something every day

20A phone sockets are for long distance calls

 

[KINKY]

20A phone sockets are for long distance calls

lol

 

[ukpablo]

yea i have plenty of times, but i dont need to get a 3 yr city & Guilds course to do it, as well as insurance and part p registration etc etc lol. im gonna ask the carpet fitter to fit my new CU next week.

And let this be a lesson to all who cut corners! Get the right person for the right job in the first place and save urself the hassle of sorting out all the crap that comes with it! You do realise that ur house insurance will be null and void now without a cert too on the new cct if it ever catches fire!!