Appliance loosing power , but no tripping of MCB's

[studentspark]

Bit of an odd one today
various appliance loosing power, but no tripping of mcbs, or rcbo/rcd

Its happening on different circuits in a nursery kitchen. Intermittently
Thought initially it could possibly be thermal cut out through over use, but not for a fridge and freezer! or dish washer.
Its all commercial equipment
dishwasher, microwave, toaster and fridge and freezer have all at some point lost power and stopped, but no tripping. each of these appliance is on a different circuit. They then start working.
Main supply is 3 phase, but the kitchen is off one phase.
Voltage is as expected on all circuits.
No loose connections on circuits.
Bit stumped, any ideas. Staff think its a ghost

Many thanks

 

[John D v2.0]

Voltage is as expected when the load are not working, or in general?
Could be a loose neutral somewhere.

 

[studentspark]

Voltage OK in general, have not been there when loss of power.
checked neutrals in kitchen DB and various sockets.
Could not check neutrals in main three phase DB as isolation was not possible

 

[studentspark]

its happened about 5 times over a month, but not the whole installation, just parts

 

[mwatsonxx]

just parts

Are they on the same phase? Remember most 3 phase equipment is not obviously affected by a fault on one phase.

 

[bernardgreen]

have all at some point lost power and stopped

When an appliance loses power do the other appliances still have power ? Seems an obvious question but maybe the person in the kitchen has noticed that one appliance has no power but has then not checked other appliances to see if they have power or are also without power..

 

[studentspark]

Yes all on same phase. no equipment in the kitchen needs 3 phase power.
Cant be a loss of the whole phase as that would take out the lighting as well.
Fridge has only lost power once I understand, as they check this quite quickly.
I didnt get much useful info from the staff, such as duration of the outage, times or what was in use.
Just very vague information about appliances sometimes not working

 

[JohnW2]

Just very vague information about appliances sometimes not working

Have there been times when more than one appliance would not work?

Is it possible that the problem is with the appliances, rather than the supply/circuit?

Kind Regards, John

 

[scousespark]

Has there been any work done in the property?

 

[John D v2.0]

Give them a checklist/questionnaire to fill in as soon as a problem occurs. Then you should get the info.

 

[mwatsonxx]

I have worked on a few kitchens that have EPO systems, a faulty one fits your description. Or another piece of equipment dragging down the voltage, such as a large Skil saw.

 

[John D v2.0]

another piece of equipment dragging down the voltage, such as a large Skil saw.

Always after a particularly tough steak is served?