Power off but all RCBOs and main switch on

[bloxy]

We keep losing power to entire installation despite power to the meter. The board is 17th edition with all RCBOs 6 circuits. Power to entire house goes off but nothing trips on the board, all RCBOs still on but test buttons don't operate and main switch still on but no power. Meter shows power and using my Fluke voltage tester I can see there is power at the incoming side of the main switch but nothing at the outgoing side.
Turn off all RCBOs, turn off main switch and turn back on, turn on RCBOs and power restored and all test buttons operate correctly, sometimes its necessary to cycle the main switch a few times to get power.
My thought is that the main switch is faulty and randomly disconnecting despite being in the on position.
As any one come across this type of fault?

 

[EFLImpudence]

I have never come across this but if things are as you describe, I would agree with your diagnosis.

Are you measuring actual voltage with a two pole tester or just pointing a thing that lights up at the switch?

 

[bloxy]

Tested with proper two pole Fluke voltage tester. Not a lighty up thing!

 

[Murdochcat]

Loose neutral in the service head …. Or faulty main switch

 

[bloxy]

Loose neutral in the service head …. Or faulty main switch

If if loose neutral in the head there wouldn't be power at the meter would there?

 

[DetlefSchmitz]

Has anyone said loose wire in the main switch yet?

 

[bloxy]

Has anyone said loose wire in the main switch yet?

Checked all tight and good

 

[SUNRAY]

Has anyone thought to agree the tests performed do indeed point to a faulty main switch, assuming that all leads are correctly terminated.

It did seem to be an issue with 60A main switches in older fuseboxes (particularly MEM ceramic rewirable types) when loads increased.

 

[DetlefSchmitz]

Well, EFLI said in post #2. "I have never come across this but if things are as you describe, I would agree with your diagnosis." This is why I assumed we had a diagnosis by now.

 

[flameport]

My thought is that the main switch is faulty and randomly disconnecting despite being in the on position.

That, or the busbar connection is wrong, as in the bar is behind the terminal cage rather than in it.

 

[pete01]

I had this in my own house a few years back, the consumer unit was already installed when I moved in.

when I moved the first mcb (next to the main switch) there was a burn mark on the main switch , maybe you you have a similar issue?

 

[LeeJC]

Smart Meter?
Just a thought that they can disable these things remotely..... and I'd suspect electronics over electrics for the kind of intermittent issue you're seeing everyday.

Ignore that.......... you checked the incoming/outgoing side of the switch in failure............ I'll learn to read honest guv.

 

[Murdochcat]

If if loose neutral in the head there wouldn't be power at the meter would there?

if it’s just touching it may show as live ….

 

[securespark]

Could the main switch be faulty just on one pole?

 

[bloxy]

That, or the busbar connection is wrong, as in the bar is behind the terminal cage rather than in it.

Had the bus bar out and checked, all looked good and then replaced correctly.