Tripped the mains

In my hi set up in which there are two Super caps and a 555PS are always on. However i noticed of the four banks which they are plugged into and in the wall socket that someone had switched it off (no one claims to have done it, there’s only two of us). When i switched it on again it kept tripping the mains, but when i switched the power supplies on individually it was fine. Would there be enough current in the power supplies when switched on simultaneously to trip the mains ?

My Hicaps do the same, i switch on one at a time, seems normal with your even bigger PSUs

1 Like

It would make sense, when i switch on my six 135’s at two at a time, i notice there’s a slight flicker if the lights are on in the room.

And at the power station!

3 Likes

It’s completely normal, transformer inrush current is the cause.
Switching on one at a time should always be the way it’s done.
This subject may generate questions about the rating & type of circuit breakers, but switching on one at a time is still the way to do it.

2 Likes

Have a look here:

Hi Fi MCB on Consumer Board Tripping - Hi-Fi Corner - Naim Audio - Community

1 Like

Naim recommend a 32A Type C MCB / RCBO. This has a higher in-rush current rating, so should reduce nuisance tripping.

1 Like

My first Nain power amp, a 250 on the GF ring maim used to make the living lights dip on switch on and that’s on a differnt ring.
For a few years all my kit has been direct off a spur from the consumer unit, including the 500DR. No problems in this mode.

Now funny you say that, but the Power Station i work at, we have some 11Kv machines (motors driving pumps) that do dim the lights on site. I guess starting a 20,000hp motor does that. National Grid get very unhappy if we put too many starrs on these machines over a shirt period!

2 Likes

Interesting stuff, cheers

First time I stood next to the air circuit breaker, was an education. Watching an ammeter go off scale ( 2,000A) for 6 or so seconds. The bus bars rattle.

1 Like

Yes, Quite possibly, if you had not switched off the individual equipments, before applying the mains to all of them simultaneously. It’s called “Inrush Current”.

1 Like

Our Ground Source Heat pump does dim the lights on startup and that is the “soft start” model. Talking of big motors, the 13 X 9 wind tunnel at BAe Weybridge had a 2200HP motor. We had to phone the electric company warning ahead of running it up. The top speed was also limited in the winter months as they didn’t want us taking too much load off the grid.

2 Likes

I used to work for an electrical engineering company. The head office was in Bonn, where the type test labs were based. At one stage they had the largest test surge generator in Europe. I remember one time watching the testing of a Distribution Board to test the fault rating of the Circuit Breaker, rated at 6300Amps. We watched behind ballistic glass with Purple colour eye shields. It started off fairly dark, then there was an incredible flash. Once the room cleared of smoke, etc, we checked what was left, all the copper buss-bars had vapourised. The remarkable thing was that although the board and equipment was totally destroyed, the breaker had contained the fault and it wasn’t passed downstream.

2 Likes

Then i’ll have one of them so it won’t happen again. LOL.

Yes, we followed that advice as the 'geddon was the culprit. It helps if you have a separate spur.

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.