Too much surge protection?

[Vicario]

My new CU has an SPD fitted next to the main switch. I have several extension leads which have surge protection so do I need to replace these now or is it OK to continue using them?

 

[Harry Bloomfield]

You can continue to use them if you wish.

 

[mattylad]

Consider them as "additional local protection".

 

[flameport]

You can keep using them. They might actually be useful now that you have the SPD in the consumer unit.

Previously they were next to useless.

 

[aptsys]

You can keep using them. They might actually be useful now that you have the SPD in the consumer unit.

Previously they were next to useless.

That's completely untrue. How did you arrive at that opinion?

 

[Harry Bloomfield]

That's completely untrue. How did you arrive at that opinion?

The simple, cheap version is a use once only - Once the surge protection has been used, they tend to blow and offer no further protection.

 

[bernardgreen]

There were in the past ( and probably still are ) sacrificial surge protectors. Their one time function was to switch ON when the voltage went above the maximum safe voltage and connect Live to Neutral for long enough for the fuse and/or MCB to react and cut off the supply.

This could damage the surge protector so best practice was to replace them after they had operated.

 

[bernardgreen]

Can you have too much surge protection ? If the circuit is RCD protected ( Earth leakage ) then the amount of Earth leakage current created by the surge protectors could be enough to trip the RCD. Surge protectors ( or supply filters ) have capacitors between Live and Earth and between Neutral and Earth and these create Earth leakage current.

 

[Harry Bloomfield]

There were in the past ( and probably still are ) sacrificial surge protectors. Their one time function was to switch ON when the voltage went above the maximum safe voltage and connect Live to Neutral for long enough for the fuse and/or MCB to react and cut off the supply.

This could damage the surge protector so best practice was to replace them after they had operated.

Best practice and what normally happened was the fuse was replaced, or MCB reset, but nothing done about the surge protection.

 

[SUNRAY]

You can keep using them. They might actually be useful now that you have the SPD in the consumer unit.

Previously they were next to useless.

To be honest the way SPD's are installed in CU's is next to useless also.

 

[Harry Bloomfield]

To be honest the way SPD's are installed in CU's is next to useless also.

I suspect the same. Only a device which doesn't self destruct will survive doing it's job.

 

[JohnW2]

To be honest the way SPD's are installed in CU's is next to useless also.

As I keep saying, we now have "a solution", but a solution to a problem that I am far from convinced significantly exists - and that remains the case no matter where/how SPDs are installed.

Kind Regards, John

 

[SUNRAY]

I suspect the same. Only a device which doesn't self destruct will survive doing it's job.

It's not that, it's the long leads connecting the device to an mcb.
So it MAY attenuate a surge.
It MAY trip the mcb.
It MAY self destruct
But what it won't do is prevent a surge getting to the outgoing circuits.

 

[Vicario]

My electrician said that my leads were the cause of a low IR reading on the upstairs ring and that they could trip that RCD.

 

[Harry Bloomfield]

My electrician said that my leads were the cause of a low IR reading on the upstairs ring and that they could trip that RCD.

Sounds a bit unlikely - not your story, but the reason for low IR.