Surge Protection?

[yellowvanman]

Just had a call from a guy with the following scenario:

New 17th edition board put in 12 months ago (by others)
In the last couple of months the RCD for the ring (with freezer) has tripped twice coincedently with 2 thunderstorms. So obviously thinks that thats the cause of the tripping. Although not sure how far away any lightening was from his house, and its not on a hill!

I've mentioned the possibility of fitting surge protection, but would that stop this problem? Could such surges trip RCDs?

 

[Brendan976]

Much More likely rain getting into an outside light or socket.
Ben

 

[yellowvanman]

Much More likely rain getting into an outside light or socket.
Ben

Thats more likely the problem! Will have to discuss more about how/when the trips happened!

 

[bigbaddave]

I agree with the above. Its just unfortunate with thunder there is rain..

 

[yellowvanman]

Just made a visit:

No signs of water ingress anywhere and since the first trip its rained quite a lot.

Now thinking along the lines of:

Telephone has a surge protector, which is plugged into the ring main on the RCD side that tripped. If during a thunderstorm that surge protector initiates then (as far as my understanding goes) it sinks the overvoltage to earth - in which case RCD will probably trip.

Does that sound logical?

 

[grantr37]

surge protector/surge adapter would do that, needs to unplug the phone from the wall to stop that from happening....it's generally at over 90V induced on the phone line that this happens....saves the phone base station or handset if corded...otherwise it will break and need throwing out/replaced.....

 

[gnuuser]

surge protector/surge adapter would do that, needs to unplug the phone from the wall to stop that from happening....it's generally at over 90V induced on the phone line that this happens....saves the phone base station or handset if corded...otherwise it will break and need throwing out/replaced.....

correct if a phone line is near enough to a power line it can induce unwanted voltages
we had issues of this destroying computer equipment (even with surge protectors)
had quite a hassle with phone company until we showed them where the problem was.
o-scope monitoring (dual trace) of phone line with direct connect channel 1 and inductive connection channel 2
it displayed inductive spikes of 150 volts causing damage

 

[yellowvanman]

Ok, so this is protecting against a surge in the telephone line rather than in the power line?

In which case if I installed a SPD before the RCDs (at incomer to building) that wouldn't provide the same protection to what exists and remove the need for a surge protector on the telephone line and cure the RCD tripping in a thunderstorm?

 

[ackbarthestar]

It appears that thunderstorms are happening on other forums as well.
You might like to have a look at this one:

IET Forums - Can an SPD trip an RCD?

 

[gnuuser]

shunts work well in a lot of circuits
heres a wiki on it
Shunt (electrical) - Wikipedia, the free encyclopedia
there are many types of shunt circuits you can use including isolation transformers and voltage conditioners.
but all this depends on what needs protecting.
living near a large power source or factory with heavy current draw can cause a variety of brown-out and spikes
a large electric motor if stopped suddenly will produce a frightfully large feedback charge as the magnetic field collapses and it happens in less than .01 of a second
clamping circuits may be needed prevent damage

 

[yellowvanman]

It appears that thunderstorms are happening on other forums as well.
You might like to have a look at this one:

IET Forums - Can an SPD trip an RCD?

Thats me in another guise!

 

[ackbarthestar]

Yes I know the sydrome,
I'm a right old tart who hangs around Greek Street in a Gorilla costume.......