fault today at work 400v live to neutral

[Knobhead]

I’ve been using GE System4 and MiniForm for near 40 years, damn good reliable switchgear.

I only had one switch over heat and that turned out to be the fuses had been incorrectly installed.

 

[sparksburnout]

Tin hat on - I have no practical knowledge of 3P systems only theory, but I am a bit surprised that the switchgear appears to interrupt the neutral as well as the 3 phases, given the implications and dangers highlighted in this thread, is this usual?

 

[jonney88]

my appologies the section panel is proteus I was using the term mini-form,, it's not your usual section panel filled with 60947-2 mccb's there bs 88 so thought that's were called miniforms,, thinking bout it miniforms have the sliding fuse tray,, but this section panel Engadget on to the neutral bar behind the switchgear its a rubbish set up no room to work m6 terminals for connections which are incredibly difficult to get to, I hope they don't make these things any more ther s nightmare to work on

 

[Darkwood]

Tin hat on - I have no practical knowledge of 3P systems only theory, but I am a bit surprised that the switchgear appears to interrupt the neutral as well as the 3 phases, given the implications and dangers highlighted in this thread, is this usual?

Switchgear with 'early make' - 'late break' Neutrals should be used to avoid a floating N on switching which can do alot of damage even if just for a short period....... the need for switching N is another debate altogether and on a domestic level it is required that all Lives are isolated at the main switch (L/N in domestic case been 1ph commonly) as it is a switch that a general member of the public may be expected to operate - - commercial and industrial especially 3ph becomes a whole different kettle of fish

 

[UKMeterman]

Hmm,
There are three things that spring to mind.
1. I do think you need to inform the powers that be that you found a fault that would have caused a catastrophic failure of all equipment connected to that switch fuse with the risk of fire.
2. Do you have an inspection program for main switch gear including thermal monitoring / inspection?
3. What lock out procedures do you have and do you know what the term arc flash means?

 

[Knobhead]

Hmm,
There are three things that spring to mind.
1. I do think you need to inform the powers that be that you found a fault that would have caused a catastrophic failure of all equipment connected to that switch fuse with the risk of fire.
2. Do you have an inspection program for main switch gear including thermal monitoring / inspection?
3. What lock out procedures do you have and do you know what the term arc flash means?

What the hell are you talking about?