Thread: Surge protection

Tripp Lite make a 3900J surge protector for about US$75 but its only available in 120V versions and its not sold by anyone into Australia.

The most likely V surge through mains lines in an Australian workshop is lightning strike but it would cost a lot more than US$75 to protect against V surge from this.
Lightning strikes also often cause damage by completely bypassing the mains line and surge protector.
For example if lightning were to strike a shed wall near the DP it could create a 100,000V/m field in the surround ground sending a few 10000V up the DP column - no surge protector is going to protect against this.

In terms of general surge protection my understanding is they are really only needed for use where power generation is haphazard eg a 3rd world country, or maybe in places like a large metal workshop with lots of big machinery or welders switching on.

Thanks Bob .... as always!

Most households have built-in surge protection, but this is against personal injury, as I understand. What constitutes a reasonable level of extra protection for computers for the usual spikes/surges in electricity? I know you say we should not have them, but we do. Furthermore, there is an industry built around cheap surge protectors - is this a scam?

I have found a couple of surge protectors available locally (after a long, long search):

This one states 4890 joules into 1 outlet and 1750 joules into all of its 8 plug points. I wonder how many joules protect 2 plugs? https://www.catch.com.au/product/tho...xoCCSYQAvD_BwE

This Belkin has 2142 joules into 8 outlets. They do not mention dropping off, as above. Belkin Pro Series 8-Way 3M Cord Surge Protector with AV, Tel & F-Type BV108130AU3M


Your thoughts?

Regards from Perth

Derek

Here’s another link that may help
Surge Protector | Mwave

Originally Posted by derekcohen

Thanks Bob .... as always!

Most households have built-in surge protection, but this is against personal injury, as I understand.

If you are referring to RCDs then these are not surge protectors as they operate at 240V and are a device that compares the current going through the mains active and neutral lines. If there is a mismatch then that means current is being lost elsewhere (possibly though a person) so it switches off the mains.

What constitutes a reasonable level of extra protection for computers for the usual spikes/surges in electricity? I know you say we should not have them, but we do. Furthermore, there is an industry built around cheap surge protectors - is this a scam?

Yeah I reckon its a bit of a con especially those protectors that hint at protecting equipment against lightening strikes since the type of strike they can protect against is relatively low risk and it's not we're protecting a piece of "essential for life" equipment. Against lightening strikes close to the device they are virtually useless because "close by lightening strikes" can drive currents through device circuitry direct through the air or any insulator. At short range it's effectively the same as EMP.

Inside homes, surges can be produced by things like large older AC units and fridges but newer versions of these should not produce surges. If your lights dims dim when you turn a device on or they brighten when you turn them off then this is indicative of something that is probably producing a power surge - in that case the device should be looked at by a sparky rather than fitting a surge protector to every other device in the house.

If you lived/worked very close to or operated the DP in an industrial area where lots of big machinery or welders was continually being switched on and off then there might be a case for using one but where you live I'd say that risk is very low.

Here is an interesting CNET FAQ about surge protectors.
10-things-you-should-know-about-surge-protectors

And a little further on down the article it says
"Note that CNET may get a share of the revenue if you buy anything featured on our site."