I hate plumbing and have a old Hitachi water pump I changed the pressure switch because the old one started not to turn off the pump unless you switched it off.

 

I have fitted a new pressure switch same type etc and was working fine then later when pump was switch on it trip out all power.

 

If a tap is turned on already the pump works when I turned the water off the 'T' cut trip out all power. 

 

No water turned on switch pump on power trips out all power. 

 

Could a pressure switch cause this is the question or is something else going wrong with the old pump.

Which breaker is opening (over current or earth leakage)? If not sure post a photo of the T cut after it has tripped.

 

Any damp/wildlife got in to the pump or local wiring?

There could be a short or partial short circuit within the pump that would manifest when the pressure switch closes.

1 hour ago, Crossy said:

Which breaker is opening (over current or earth leakage)? If not sure post a photo of the T cut after it has tripped.

 

Any damp/wildlife got in to the pump or local wiring?

The T cut is 30mA the only one that is tripping not the inline trip switch in the consumer unit. 

The pump is only the 15 amp trip switch in the consumer unit but that doesn't trip.

I saw the pressure switch flashing when the water was on turned water off and T cut whack off. 

I have disconnected the pump from the pump indoor switch and turn the indoor switch on and it doesn't trip so everything point to the pump you think. 

 

Definitely sounds like the pump has gone leaky ???? 

 

You could try swapping L-N at the pump.

 

6 minutes ago, Crossy said:

Definitely sounds like the pump has gone leaky ???? 

 

The wire to pump I will test a fan on just to rule out any problems. 

 

And run a extension lead to the pump to see if its definitely the the pump which I agree with is done for, it is 18 years old so a good innings I guess. 

 

Thanks for helping. 

 

Internal wiring seems OK to outside.

Fan test very professional. ????