My music PC and other audio equipment was once plugged into a surge-protected mains extension lead. But that didn't last too many years (as I understand it these things use metal oxide varistors which can 'go' during higher energy spikes), so I want to get a replacement.
Are there any better (yet still affordable) answers, or do I just buy or make another protected mains extension lead and accept that it (or maybe just its MOVs) will need replacing periodically?
Thanks,
Kev
Are there any better (yet still affordable) answers, or do I just buy or make another protected mains extension lead and accept that it (or maybe just its MOVs) will need replacing periodically?
Thanks,
Kev
I bought a couple of protectors made by ZeroSurge and have been very pleased with them. Rather than bare-naked MOV "pure voltage clamp" circuitry, these incorporate filter-then-clamp circuits as discussed in the heavy-with-marketing sales blurb attached below.
It took a little while, but I was eventually able to find one of their US Patents, also attached. The drawings show how the filtering and clamping are implemented. In my opinion, it's a cute (and a great) idea.
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It took a little while, but I was eventually able to find one of their US Patents, also attached. The drawings show how the filtering and clamping are implemented. In my opinion, it's a cute (and a great) idea.
_
Attachments
Those surge protected mains outlets / extensions don’t really work because they are too weak.
They are useful if part of a three tier system: A huge surge protection right at the house inlet, a smaller one at the inlet of your flat and then the tiny one at the mains outlet where you plug in the device to be protected from surges.
Surges are less common with buried power cables, but more common with overhead power lines.
They are useful if part of a three tier system: A huge surge protection right at the house inlet, a smaller one at the inlet of your flat and then the tiny one at the mains outlet where you plug in the device to be protected from surges.
Surges are less common with buried power cables, but more common with overhead power lines.
MOVs are more reliable when limiting the current through them, for instance to the maximum value the household might need. In my case, a 20A thermic fuse does a good job (applied MOVs can take kA) and over the thermic fuse a LED, antiparallel with 1N4148, in series with ~150k is used to indicate "temporarily switched off". As the input lines are 120V opposite phase, each line is treated that way, and the "protected" 240V output is run through a transformer, 240 to 120V. The installation has been working well since 2017. As I've witnessed the red LEDs turning on several times during "close hits", it's a solution I can recommend. In the middle is a switch to turn off grid connection during power cut, so I can connect a generator to any outlet.
Thanks everyone, that is useful. It does seem that some are better than others, then. I'm not expecting total elimination of all possible spikes, but whilst there are a fair number of them, happily we rarely get huge ones here (perhaps as above, because the cables are burried).
I might possibly have a go at making my own then. Or failing that, trying a different brand with a better joule rating; it looks like APC make some UK types for instance, and I've been pleased with their Uninterruptible Power Supplies over the years.
Thanks again!
I might possibly have a go at making my own then. Or failing that, trying a different brand with a better joule rating; it looks like APC make some UK types for instance, and I've been pleased with their Uninterruptible Power Supplies over the years.
Thanks again!
I'm quite happy with my APC UPS. Here in the wilds of Brittany we get a lot of thunderstorms, and the local farmers piling their round bales too high on their trailers tend to take down power lines from time to time. The APC saved my bacon one evening then lightning struck the transformer 50 yards up the road from me. Destroyed the transformer and everything near it. Big bang, lights went out, but computer and hifi didn't miss a beat.
That is encouraging to hear, and yes; I too have had good results from their UPSs (both small ones at home and bigger ones at work). So for now I decided to try one of their surge arrest power strips to see how that goes. Hopefully well, but if not then I'll next try the DIY approach, such as Aridace did above.