Surge protector is a lie?

What's the point of any of them? Zero. But fools buy em.

Simple. When the light goes out you give Micromark more of your money...but I think you knew that.

Well, it is probably only meant for spikes caused by things switching on and off. I did, some years ago buy a packet of Surge protection vdr devices from RS and fitted them inside plugs where there was room. One day there apparently was a lightening strike nearby, and my stuff was fine except for

Of course if you do really get a very local strike, I have seen the result in a local factory. Every bit of electronics had its mains input circuit trashed and nearly all the internal wiring had to be replaced and the sockets were in fact blown off the wall and melted. Really a sobering thought. Brian

I'd not say all are rubbish though. Read my last post. I still retain one. You used to also find those vdrs inside the mains filters you could buy made by QED and others. As I say, I don't think if the surge was from a nearby lightening strike or cable malfunction, you would stand much of a chance though. I remember that an old Amstrad PC used for machine tool control kept having its power supply die, People thought its was the muck, but that turned out to be the powerful motors in the engineering works putting spikes on the mains supply. a small box with surge protector and mains filter and no more trashed psus. I'd not venture on the mechanism, but if you use budget computers, you probability get over worked and cheap psus. Brian

snip

for most users they are. If you run on a small genny they can have a use.

I had a ground strike near me a few years ago. Apparently the surge of electricity in the ground was picked up by my satellite TV antenna's underground wire. The satellite receiver was fried AND SO WAS the UPS

• surge control unit that the satellite receiver was plugged into. Nothing else in the house was affected.

When lightning is real close, I now unscrew the dish antenna from the receiver and just watch things that I had previously recorded.

-dan z-

Cheap chinese appliances with fake UL and CE labels need fake chinese surge protectors with fake UL and CE labels.

Micromark seems to be sold in the UK but not in the US.

Surge protectors are a lot cheaper than appliances like microwave, TV or computer. I had problems with all before using surge protectors. Living in a treed area, high tension line would fall onto low tension line to houses causing the voltage surge.

Guessing, the varistors absorb a quick surge, and the "fuse" doesn't blow. If the surge is enough to blow the electronics and cause them to short circuit, the "fuse" blows and avoids the gadget to cause damage to the rest of the house. Of course, the spike could still blow the house, but you will not be able to sue Micromark for it.

Obviously, there is some complicated rationale for what was done.

If you look at a proper design, the protective components have barriers placed next to them, to contain shrapnel. And this is to prevent the protection block from becoming a flame thrower or punching holes in adjacent components.

The components are also placed in a metallic housing (for fun).

So it is possible to make a surge arrestor with some useful properties. Not all of these things need to be a joke.

Paul

In general if you have SMPS on the rings, you have what amounts to an 8 amp + capacitor surge limiter right there and short transients wont get through the mains filters anyway.

In short if you get a surge big enough to be a problem it will take out the surge arrestors only anyway.

My time in S Africa taught me that nothing is proof against near wire strikes except physical isolation - transformer or opto coupler.

And if you get a full wire strike, all bets are off. You will be jumping across any short gap anywhere nearby.

Full carnage.

Surge absorbers have their uses, namely on small gens which produce inductive spikes on loadshed. On mains feeds they're pretty much a joke at the expense of the consumer. Consider the impedance of the average mains supply, a lump of nonmetal isn't going to do much in comparison. Consider the lump's size, it's never going to handle a real hit. What you're really buying is a questionable value insurance policy/scam plus a fire risk.

Varistors usually fail short-circuit, hence the fuse. There's no point wasting money on a breaker in that position.

HT lines generally do not cross over LV lines for this reason.

All the places where I have seen this happens there is always an additional bare copper earth line above the 3 phases and neutral, and this extra earth is connected to earth at each of the supporting poles.

These days the LV stuff is being replaced with twisted bundles of insulated aluminium cable anyway which should minimise the problem.

I do not know about their wiring here. Service to my street is underground but above ground leads to it. In the past I recall wet branches falling causing the short between HT and LT.

the idea that a surge absorber will protect your appliances against such an event only demonstrates a failure of basic maths or the ability to even very roughly model the situation. That someone has had appliance failures is no evidence of a surge that such a suppressor would resolve. Some situations are clarified by simple maths.

The way this is done may vary between the US and UK. This is cross-posted to international groups.

Andy

Trouble is any decent surge would blow its internal fuse, which stops it protecting, and the surge then carries on to the equipment. A better way would for the fuse to also stop power to the device it's protecting. Then if the surge is too much for the surge protector, you've stopped the power to the device.

I'm going make my own, with varistors big enough to blow a 30A fuse for the whole ring main.

Well one I fitted at my work (a little plug in one by something like Techtronics) melted into a lump and drew enough current to trip a 32A breaker. It saved a roomfull of stuff from 415V.