odd rcd problem

[bobby101]

hi all got a weird fault on a rcd s/o in a shopping centre, the fault is this when a walkie takie is opoerated within the vicinity of the rcd s/o the rcd trips out ( NO JOKE ) any advice on this apart from changing the walkie talkies or replacing the s/o i would really more than anything like an explanation as to why this happens .
time to get the thinking caps on thanks vry much in advance ..

 

[Darkwood]

EMP (electro-magnetic pulse) 'spike' possibly produced when pressing the button on walky talky which can induce a voltage in sensitive coils in rcd, easy to check is have button already held in then approach rcd and walk away again, then do it by pressing talk button and see if it trips either on pressing or letting off button.
I would also talk to tech of the rcd and ask if the components are shielded, as well as see if you can change the frequency band of the walkie talkies as the coils in the rcd may be acting as amplifyers which are sensitive to certain bandwidth.

 

[bobby101]

thanks that helps

 

[bobby101]

is it possible to get a rcd s/o with a anti spike filter

 

[Darkwood]

Its only a suggestion or shot in the dark and i may be way of mark... your spike filter you mention would look at mains transients and rcd's are pretty tolerant to them but the EMP i suggest induces a voltage/current in the sensitive coils of the rcd's. Id ramp test the rcd off load and on load to see if their is earth leakage present and the walkie talkie may be just enough to push it over the edge, does it only effect the one rcd ? are others effected?.... you need to ask yourself all these questions to guide your next move.

 

[Darkwood]

If you bbc is the same its on about wireless technology tonight on Bang Goes The Theory, although its aimed at general public it may light a bulb over your head as to whats happening ....

 

[jumpin jax]

Change the s/o for a non-rcd one and put an rcd further upstream away from interference

 

[sedgy34]

hi all got a weird fault on a rcd s/o in a shopping centre, the fault is this when a walkie takie is opoerated within the vicinity of the rcd s/o the rcd trips out ( NO JOKE ) any advice on this apart from changing the walkie talkies or replacing the s/o i would really more than anything like an explanation as to why this happens .
time to get the thinking caps on thanks vry much in advance ..

SO HOW LONG HAS THIS PROBLEM OCCURED or has it always done this

 

[jumpin jax]

Or change it to a Metal clad one, this would save wrapping the existing one in tin foil!:biggrin5:

 

[bobby101]

the problem has always been there and fitting an rcbo is not possible due to location of db (in case of nuisance tripping) the s/o need to be rcd protected and fitted in in a ip rated enclosure for reasons of location/ addional protection etc ps the problem affects at least two seperate units that i am aware of

 

[jumpin jax]

Sensitivity of RCDs to disturbances - Electrical Installation Guide try this

 

[bobby101]

guess i got some reading to do tonight, thanks for the factsheet vry usefull

 

[Darkwood]

Read this section below, its possible your rcd dosn't meet requirements regarding immunity to radiowaves and i would be inclined to change it.


Radio frequency Electromagnetic fields
Within the IEC 1000 series there are two separate documents that deal with the question of Radio Frequency electromagnetic field immunity tests.

IEC 1000-4-3 covers RADIATED r.f. fields.
IEC 1000-4-6 covers CONDUCTED r.f. fields.
​

In both cases, the source of the disturbance is basically an electromagnetic field, originating from intended r.f. transmitters that may act on the whole length of cables connected to an installed equipment.
The dimensions of disturbed equipment such as RCD’s are small compared with the wavelengths involved. The incoming and outgoing leads will therefore behave as passive receiving antenna networks since they can be several wavelengths long. The scope of IEC 1000-4-6 covers the frequency spectrum of 9kHz up to 80MHz. For small devices such as RCD’s, it may be possible in the future, to test according to IEC 1000-4-6 for Conducted radio frequency fields up to 230 MHz.
The test levels for RADIATED radio frequency electromagnetic field tests for RCD’s are taken from IEC 1000-4-3 for the frequency spectrum 80MHz up to 1000MHz. This radiation is often generated by such sources as small hand held radio receivers as well as fixed and mobile radio and television transmitters.
The question of emission due to GSM digital radio telephones is still under investigation by the relevant IEC sub committee.

and with regards to jumping jax humerous comment on metal clad you have to also remember that the RF interference will effect on the circuit cables to so using metal clad socket isn't a solution .

 

[oldtimer]

Yep 26 years ago I worked with Thorn Security and fitted a 9000 alarm system in the Security of an art gallary and if they used the radio in the room it set of the PA alarm causing 2 police to rush to the scene funny thing was the guards were old so some would walk in the room and automatically answered the radio but the minute that button was pushed.......................................