The 'big bang' theory ??

[SGHOM]

We've spent the weekend earthing a generator. :thinking: Simple job..... just run a wire from gen to earth ? err..... not quite.
A 240mm earth wire to just over 100 mtrs away.. to an earth spike embeded 50 ........ yes.... 50 metres into the ground [ through the water table ] :speechles

Connected it all up, & It went into fault ?? straight earth fault ? /Grr

I'll not get technical...... but, If that gen had fired up whilst we were there.... & was in fault mode, then the question is..........................




how far down the road would a 5 ton generator have landed, when 3200 amps is put through it on start up !! :speechles :speechles :speechles

That would have been one friggin' big bang !!

[Nick Mann]

:afro:

A couple of months ago at work we blew a fuse on a 400V 3 phase panel. The fuse was 315 amps. That is not so out of the ordinary - it happens every few months or so. A couple of months ago was different, 'cause when the electrician had replaced the fuse, and I pressed the go button, the main contactor in the panel went BANG! I needed a change of underwear! It was later determined that the current hit 1000 amps when I pressed the button. Not as much, maybe, but plenty enough!!

[Kieran]

Ber-luddy-ell!! That would have been quite a sight!!:speechles

What was the cause of the fault?

[shaun1978]

I've been there when a genny has fired up and gone bang! this was on one of the slieves (mountains) in ireland and was a vodafone/police cohabited comms site, there had been an intermittent power loss on site one winter and two of us had been tasked to go get the comms eqt back up.
Got onto site and all seemed well , flicked a few trip switches and everything started firing back up so we had to wait on site for a few hours to make sure it stayed that way, 1 hr 30 mins later the power dropped again, heard the genny in a separate building starting up and BANG with a tremor , I thought it was a bomb had gone off for a start but everything was dead so i ran out side and saw smoke billowing out of the genny room , luckily enough it was armoured so it kept it inside but that site was down for months while a new genny was flown in and the sparkies rewired the whole lot, there was a few expletives expressed that day and a couple of pairs of soiled underwear lol.

[Nick Mann]

Glad no-one is being hurt in these stories!

Kieran - that furnace is one of our smaller ones, approx 150 kW, and the main coil on the inductor had got a small splash of molten metal on it that shorted out the windings. There's only about 15 windings on the coil anyway, so you wouldn't have thought going down to 12 or 13 would have made that much difference, would you?! /pan

I have no idea what the earth fault on Dereks generator was though!

[bradc]

150kw, thats nothing! Just hook up a VR-4

[Nick Mann]

Does your VR4 run at 150 kW 24/7? :P

And I did say that was a small one....

[WildCards]

Whats a big one then Nick?