Strange, Strange fault.

[nsbs]

Hi Guys.

3 months ago I installed 4 power posts in an office, each independently serviced from a 60898

 

[daveygh]

Have you asked if a cleaner comes in at night and plugs a dodgy hoover in?

 

[nsbs]

Have you asked if a cleaner comes in at night and plugs a dodgy hoover in?

yep, office completley empty, cleaner comes in at 5pm, the mcb trips after that, last night 3.15am.

 

[Sidewinder]

Can you put a voltage / current recorder on it with time stamp?

Is this close to the local sub?

Have the DNO had issues and changed the network?

Or, are they (dno)changing the network?

Or are they (dno) switching during the night?

 

[steptoe]

I had an issue with an underfloor heating system tripping an unrelated MCB, the only common connection was it was the same phase, and when the heating turned off it musta been spiking the system,

a capacitor solved that one for me.

 

[Manator]

Its got me stumped, if you have had a power meter on it overnight and still no spikes, and the fact that only one MCB is effected. The power pole has been left with no current drawing devises plugged in and it still trips. So its not thermal, and I doubt it could be magnetic faults. I would love to know what it is as I bet you would. The only thing I can think of is a fault with the power pole itself which could have an intermittent fault causing a niggle of a short. Apart from that I am totally stumped, I would swap two of the poles around and see if a different MCB trips to rule this out.

 

[batty]

Ghoulies offices may be built on a buriel site.

 

[m4tty]

Lock the mcb on to rule out ghosts lol

 

[sparkytim]

Are there heavy loadeded MCBs sitting next to the MCB that trips?

Have had thermal effect cause this. Try leaving blank space or light loads on either side.

 

[Brian 157]

I've encountered the thermal effect Sparkytim suggested, also I've known RCBOs being tripped by walky-talkies, cordless phones & passing taxis etc. MEM redesigned their RCD "pods" (Memsheild type) about ten years ago to stop this, but I've never heard this with MCBs, keep us posted when you get to the bottom of it!

 

[Doc Hudson]

Tripping a 40A MCB? thats a lot of juice assuming the MCB is working correctly! Is there any way the MCB could be temporarily be moved out of the existing DB in to a separate enclosure to isolate it from all surrounding MCB's?

Doc H.

 

[NozSpark]

If this is still happening could you run the circuit through an isolator adjacent to the CU and have them turn if off at night

If it trips with that then it's even weirder:O

 

[nsbs]

Cheers guys,

It

 

[Evans Electric]

Lock the mcb on to rule out ghosts lol

It will still trip with a lock on it M4tt , I reckon its haunted !!! Would like to know the answer though.

---------- Post Auto-Merged at 16:28 ---------- Previous post was made at 16:25 ----------

NSBS , I'd definitly replace the MCB or swop it with another to see if it still happens .

---------- Post Auto-Merged at 17:32 ---------- Previous post was made at 16:28 ----------

Also , as Sparkytim says, it could be a thermal problem from adjacent breakers . I had a simlar thing with three lighting tracks fully loaded to 16A each . Middle one started tripping on hot days. Changed them for dinrail mounted HRC fuse carriers in the end .

 

[Revved Up Sparky]

If the place is haunted then me and Revjames will exorcise the place for a small fee..... don't forget to pay our bill though or the place may get repossessed

 

[nsbs]

It will still trip with a lock on it M4tt , I reckon its haunted !!! Would like to know the answer though.---------- Post Auto-Merged at 16:28 ---------- Previous post was made at 16:25 ----------

NSBS , I'd definitly replace the MCB or swop it with another to see if it still happens .

---------- Post Auto-Merged at 17:32 ---------- Previous post was made at 16:28 ----------

Also , as Sparkytim says, it could be a thermal problem from adjacent breakers . I had a simlar thing with three lighting tracks fully loaded to 16A each . Middle one started tripping on hot days. Changed them for dinrail mounted HRC fuse carriers in the end .

thanks, i have change the MCB 3 times now, and moved to a spare slot on CU, next to two 6 amp breakers.

 

[Sidewinder]

nsbs,

What events does the recorder show?

Have you got the I/t & V/t traces?

 

[nsbs]

Yep, monitors Vt & It, It monitors repeatedly every cycle, and is downloaded onto a PC. I just scroll through to I get to the point just before the MCB trips, then interrogate it in detail from just prior

 

[Sidewinder]

Ian,

What device is it mate?

What does it give you, have you done a Fourier on it?

Can you upload some data catpures as pics?

If I have the software I'll go through the data too.

A Fourier may give you answers as it will show harmonics of the fundemental, I am guessing that this is a single pole device that is tripping?

 

[Andy™]

If the place is haunted then me and Revjames will exorcise the place for a small fee..... don't forget to pay our bill though or the place may get repossessed

Would i lie to you?!