Surge protection devices without overcurrent protection

Would the SPD type 2 overload protection still work when the SPD reaches the end of it's lifecycle?

Would the SPD type 2 overload protection still work when the SPD fails due to fault?

The fusible/ thermal  link inside the SPD is only there to operate at end of life  - the last act is to blow clear and isolate, rather than fail short.
And relying on a separate MCB has the weakness of not detecting the possible overheat associated with an steadily increasing leakage current degradation.
It is only fuse wire and a spring - if anything it will fail-safe early.

Mike

The fusible link inside the MCB

SPD?

   - Andy.

yup now edited. apologies.

You might be interested in: https://www.youtube.com/watch?v=B69R-yY6_14

   - Andy.

or https://www.youtube.com/watch?v=wD7cXGr-ZYs Big clive has a go at a single module one.

or a badly made one 

www.youtube.com/watch

Sergio Fernandez said:

Would the SPD type 2 overload protection still work when the SPD reaches the end of it's lifecycle?

Would the SPD type 2 overload protection still work when the SPD fails due to fault?

Would the MCB trip before the SPD is on fire?

A 16A MCB will happily let through about 3.6kW.  That's an awful lot of heat to dissipate in such a tiny module.

Isn't most of that energy going to earth or neutral rather than being dissipated in the module 

Given all the money that's paid to various organisations it wouldn't be that hard or expensive to test some of these devices until they fail and see what happens. Or maybe even a company like surge devices could test one or more of the busbar mounted devices to destruction and see what happens. They don't have to name products, but would be great to see claimed risks backed up with real evidence.

We are all guessing, there are companies out there with the right test kit to do it, I am fairly sure the likes of David Savery would struggle to fund a suitable test, but maybe someone would like to loan David or John Ward the facilities to run theses tests. I am sure either of them would love to have a play and would be completely neutral.

Or thinking about it. The question is how do they fail when carrying too much current. It wouldn't be that difficult to use a 3 phase supply to run 400V at a varying current through one until it fails. I realise not completely straight forward to organise, but wouldn't cost more than a few thousand, maybe less with some creative thinking and right location.

The alternative, which I quite like is to move to having the SPD connected to the protective device for a socket circuit, then the owner would also know when the SPD had failed.

During a surge, yes - so the voltage drop is for the  most part in the wiring - at a level of current you don't want to be present for any time worth considering. Hence the need to disconnect when its not a short duration surge any more, but a sustained leak. when the devices fail they become a constant leak at mains voltage at a current that could be almost anything.

Mike

Alan B said:

Given all the money that's paid to various organisations it wouldn't be that hard or expensive to test some of these devices until they fail and see what happens.

Shouldnt that be what the supplying Company should be doing to justify their certificate of compliance?

And publishing those results?

But then we can point to AFDDs with their total lack of information to the buyers/consumers as to when they will trip. I wonder if there are any stats to back up their introduction which show how many fires they have prevented. I won't hold my breath.

And back to Companies self-certifying, they sold plastic consumer units that did not self extinguish or were flammable when the product standard clearly said they should be non-combustible/self extinguishing.

Strange how none of these Companies have been taken to Court for this product failure on their part. (yes, I still have a bee in my bonnet about that!)