I’m planning on getting my homes meter box rewired and was wondering about getting a surge protector /filter thingy put in at the same time to try and deal with the ‘variable’ power supply we get here in Boganville.(surges, spikes, nasties)..
Are there any reasonably affordable ones that are any good or is it all a waste of time and money?
Have no idea Mr Bear, I have a surge protector board plugged into the power point to protect my laptop but honestly have no idea if it’s ever done anything or not.
probably the best arrangement is surge protection after ELCB, then UPS on your computer (if laptop that’s already covered)
things that matter in surge protection are the clamp voltage, the time it takes and the maximum power it can absorb. There’s the quality of the earth connection too.
generally the clamp voltage is quite a bit higher than mains voltage to allow fluctuation and some spikes.
the conduction profile of clamping action too comes into it.
probably you could have front-end surge protection in your meter box, then one at the computer too.
RCD should have said, activates from current difference between A&N, ELCB activates from current in the earth system
last power outage we had blew the circuit board on our oven (expensive fuse that circuit board)….
so it’s not something that I just want for the computer or hifi.. but everything in the house.
Bear, you really need to know what you want to protect.
Surge suppression comes in different flavours of technology.
Gas arrestors – slow but handle very large voltage excursions, mainly for protection of cabling etc. They are way too slow to protect electronics.
MOV (metal oxided resistor) – this is what you will generally find in most surge suppressors sold on the market. As they are so ubiquitous the marketing departments of each firm have outdone themselves in selling the advantages and high current ratings of these devices, the vast majority of which is complete bullshit. Medium fast response. Medium surge suppression which gradually raises over time as the devices age.
SASS (Silicon avalanche surge suppression) – what you really need if you’re trying to protect computers, TVs etc; but comes at a premium price. Very fast acting, low voltage peak surge suppression. No aging of components.
sibeen said:
Bear, you really need to know what you want to protect.Surge suppression comes in different flavours of technology.
Gas arrestors – slow but handle very large voltage excursions, mainly for protection of cabling etc. They are way too slow to protect electronics.
MOV (metal oxided resistor) – this is what you will generally find in most surge suppressors sold on the market. As they are so ubiquitous the marketing departments of each firm have outdone themselves in selling the advantages and high current ratings of these devices, the vast majority of which is complete bullshit. Medium fast response. Medium surge suppression which gradually raises over time as the devices age.
SASS (Silicon avalanche surge suppression) – what you really need if you’re trying to protect computers, TVs etc; but comes at a premium price. Very fast acting, low voltage peak surge suppression. No aging of components.
Eeek, that last should be SASD – Silicon Avalanche Suppression Diodes.
sibeen said:
Bear, you really need to know what you want to protect.Surge suppression comes in different flavours of technology.
Gas arrestors – slow but handle very large voltage excursions, mainly for protection of cabling etc. They are way too slow to protect electronics.
MOV (metal oxided resistor) – this is what you will generally find in most surge suppressors sold on the market. As they are so ubiquitous the marketing departments of each firm have outdone themselves in selling the advantages and high current ratings of these devices, the vast majority of which is complete bullshit. Medium fast response. Medium surge suppression which gradually raises over time as the devices age.
SASS (Silicon avalanche surge suppression) – what you really need if you’re trying to protect computers, TVs etc; but comes at a premium price. Very fast acting, low voltage peak surge suppression. No aging of components.
Cheers Mr Been… how much is “premium”.. for the SASS thing?? I really want something that acts as a filter / suppressor / cleanser type thing that protects me from “spikes” that seem to happen at the same time as minor blackouts/brownouts, more than trying to stop a direct lightning strike
Dropbear said:
sibeen said:
Bear, you really need to know what you want to protect.Surge suppression comes in different flavours of technology.
Gas arrestors – slow but handle very large voltage excursions, mainly for protection of cabling etc. They are way too slow to protect electronics.
MOV (metal oxided resistor) – this is what you will generally find in most surge suppressors sold on the market. As they are so ubiquitous the marketing departments of each firm have outdone themselves in selling the advantages and high current ratings of these devices, the vast majority of which is complete bullshit. Medium fast response. Medium surge suppression which gradually raises over time as the devices age.
SASS (Silicon avalanche surge suppression) – what you really need if you’re trying to protect computers, TVs etc; but comes at a premium price. Very fast acting, low voltage peak surge suppression. No aging of components.
Cheers Mr Been… how much is “premium”.. for the SASS thing?? I really want something that acts as a filter / suppressor / cleanser type thing that protects me from “spikes” that seem to happen at the same time as minor blackouts/brownouts, more than trying to stop a direct lightning strike
Around $300 to $400.
A MOV unit will be way cheaper, but may not do the job.
sibeen said:
Dropbear said:
sibeen said:
Bear, you really need to know what you want to protect.Surge suppression comes in different flavours of technology.
Gas arrestors – slow but handle very large voltage excursions, mainly for protection of cabling etc. They are way too slow to protect electronics.
MOV (metal oxided resistor) – this is what you will generally find in most surge suppressors sold on the market. As they are so ubiquitous the marketing departments of each firm have outdone themselves in selling the advantages and high current ratings of these devices, the vast majority of which is complete bullshit. Medium fast response. Medium surge suppression which gradually raises over time as the devices age.
SASS (Silicon avalanche surge suppression) – what you really need if you’re trying to protect computers, TVs etc; but comes at a premium price. Very fast acting, low voltage peak surge suppression. No aging of components.
Cheers Mr Been… how much is “premium”.. for the SASS thing?? I really want something that acts as a filter / suppressor / cleanser type thing that protects me from “spikes” that seem to happen at the same time as minor blackouts/brownouts, more than trying to stop a direct lightning strike
Around $300 to $400.
A MOV unit will be way cheaper, but may not do the job.
I’m happy to pay that, if it would do a decent job …
Around $300 to $400.
that’s pretty good i was expecting a lot more than that.
in practical terms three types
plug types that are part of a power board you can buy at big W or similar / dick smith/ jaycar
used to protect whatever is plugged in to the board
pros
quick to install – you plug into normal socket
easy to use
cheap
comes with a warranty of sorts
cons
only protects what’s plugged into board
only works once – you need to buy another one when it trips – this can get expensive
hard wired or plug in types at a main switchboard or distribution board
pros
protects everything on the circuit it protects
seems to do the job
cons
slower and more expensive to install, normally had its own enclosure of sorts
may need to be hard wired in by an electrician if it only works once, or may be resettable ??
a small light is lit when it’s protecting the circuit
possibly some dedicated device that takes the power in from the switchboard , filters and homes the power being supplied , the filter might / should be built to deal with voltage spikes
pros
I’d wager they would be out there for household supply
supplies filtered power to all devices in house
might have some easily changeable fuse in the event if voltage spike
would come with guarantee of sorts and warranty
cons
expensive
hard wired
the transformers you see in the streets have a solid state device that is connected from the phases to earth
when lightening hits the solid state device ( a small black plastic block) it’s resistance to earth breaks down when exposed to high voltages, current from the lightning and the power provider then flows to earth
when the high voltage disappears resistance to earth increases and all power flows to the customer
you might have the momentary “ brown out” when lightning hits power lines
it’s because that small block is directing the current down to earth
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your house
I worked somewhere where if the surge protector board had already blown and lightning struck it would take out the brains of the salt water chlorinator
if you get the whizz bang type do your research
wookiemeister said:
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your house
yeh that’s what I’m really considering…
The electrician who did some work for us recently said they have a new estate going up near by and the whole suburb is having issues with the supply – overvoltages and the like …
transition said:
RCD should have said, activates from current difference between A&N, ELCB activates from current in the earth system
they can’t be used for surge protection
the other thing is that if its not lightning but an elevated voltage well beyond 240vac the rcd still won’t help you , it’s only measuring current difference in most cases
you can get the rcd with the white wire connected to earth but I’m not sure it’s designed to trip on elevated voltage
Dropbear said:
wookiemeister said:
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your houseyeh that’s what I’m really considering…
The electrician who did some work for us recently said they have a new estate going up near by and the whole suburb is having issues with the supply – overvoltages and the like …
measure the voltage active to earth of a night when there’s less current being used
if its at around 250vac that could spell problems
they could have had the cables from the transformer way too long and they are jacking up the voltage to account for the voltage drop
it sounds suspiciously like a voltage regulation. problem on the power authority side rather than lightning
the zone transformer automatic tap selector may be playing up and supplying voltage that’s way too high, the theoretical current on the relay in the zone substation may be faulty or set to the wrong level
Dropbear said:
wookiemeister said:
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your houseyeh that’s what I’m really considering…
That would cost da bomb.
I would call the local power authority and get then to get the “ voltage regulation “ team to look at the voltages in the area
my bets are they already know what the problem is and its an expensive fix
sibeen said:
Dropbear said:
wookiemeister said:
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your houseyeh that’s what I’m really considering…
That would cost da bomb.
get a good multi meter ( cat4) or one rated to measure voltage at the socket and measure active to earth voltage and different times of the day and night to see if system voltage is getting too high
wookiemeister said:
sibeen said:
Dropbear said:yeh that’s what I’m really considering…
That would cost da bomb.
I would start with calling the power authority and get them to investigate the voltages in the problem areaget a good multi meter ( cat4) or one rated to measure voltage at the socket and measure active to earth voltage and different times of the day and night to see if system voltage is getting too high
sibeen said:
Dropbear said:
wookiemeister said:
if you are worried about voltage surges and if they happen on a regular basis I’d be looking at a hard wired box of tricks that conditions the voltage flowing to the load in your houseyeh that’s what I’m really considering…
That would cost da bomb.
how big a bomb???
Dropbear said:
sibeen said:
Dropbear said:yeh that’s what I’m really considering…
That would cost da bomb.
how big a bomb???
Do you mean Megatons or Megadollars?
Dropbear said:
sibeen said:
Dropbear said:yeh that’s what I’m really considering…
That would cost da bomb.
how big a bomb???
Way, way too much, and you don’t need it. Put in a decent surge suppressor and if you need continuous power on anything buy a small UPS. Trying to regulate the mains voltage coming into your property is prohibitively expensive.
wookiemeister said:
I would call the local power authority and get then to get the “ voltage regulation “ team to look at the voltages in the areamy bets are they already know what the problem is and its an expensive fix
My guess is that they couldn’t give a rats as the power they provide is with specification. Believe me, the specs are fairly wide :)
Do others in the suburb have problems as well?
Perhaps their is something legal you can done if its the electricity provider who is at fault
>a high voltage spike from lightning may easily bridge that gap created by an opening RCD
>they can’t be used for surge protection
except they are every time they operate and detect any substantial difference of current between A&N, which need not be leakage to earth, as for the break current max and flash over voltages still these is not unsubstantial in RCD devices I wouldn’t have thought, so likely having an RCD inline before a voltage clamping device would be helpful. Lightning need not be one fast pulse either, it can be multiple that vary in intensity, and further once the RCD is open there’s good chance the bulk of discharge will mostly divert to a lower impedance path elsewhere.
transition said:
>a high voltage spike from lightning may easily bridge that gap created by an opening RCD
>they can’t be used for surge protectionexcept they are every time they operate and detect any substantial difference of current between A&N, which need not be leakage to earth, as for the break current max and flash over voltages still these is not unsubstantial in RCD devices I wouldn’t have thought, so likely having an RCD inline before a voltage clamping device would be helpful. Lightning need not be one fast pulse either, it can be multiple that vary in intensity, and further once the RCD is open there’s good chance the bulk of discharge will mostly divert to a lower impedance path elsewhere.
An RCD does not protect against a voltage surge.
>An RCD does not protect against a voltage surge.
Yes but voltages surges cause current surges, and where surges cause current differences between A&N…..
For example, let’s say the power line outside your house gets hit by lightning, the active supply into your earthed computer pushes up ‘round couple KV, then somewhere in the power supply it’s shunted to chassis earth.
Good chance the RCD will notice that.
sibeen said:
transition said:
>a high voltage spike from lightning may easily bridge that gap created by an opening RCD
>they can’t be used for surge protectionexcept they are every time they operate and detect any substantial difference of current between A&N, which need not be leakage to earth, as for the break current max and flash over voltages still these is not unsubstantial in RCD devices I wouldn’t have thought, so likely having an RCD inline before a voltage clamping device would be helpful. Lightning need not be one fast pulse either, it can be multiple that vary in intensity, and further once the RCD is open there’s good chance the bulk of discharge will mostly divert to a lower impedance path elsewhere.
An RCD does not protect against a voltage surge.
Actually, I’ll expand upon that.
Surge suppression devices are tested with a voltage waveform with an 8 μS rise time and a 20 μS fall time.
A MOV will operate (clamp) in around 10 nano seconds.
A SASD will operate (clamp) in around 10 pico seconds.
A RCD, even if it detected a voltage spike – and it probably won’t – takes somewhere between 2 to 5 milliseconds to open. So basically there is about 6 orders of magnitude difference in the timing of operation between a MOV and an RCD. 9 OoM if you’re talking an SASD.
Even if an RCD did detect and open, the horse has just bolted, it has died of old age.
sibeen said:
sibeen said:
transition said:
>a high voltage spike from lightning may easily bridge that gap created by an opening RCD
>they can’t be used for surge protectionexcept they are every time they operate and detect any substantial difference of current between A&N, which need not be leakage to earth, as for the break current max and flash over voltages still these is not unsubstantial in RCD devices I wouldn’t have thought, so likely having an RCD inline before a voltage clamping device would be helpful. Lightning need not be one fast pulse either, it can be multiple that vary in intensity, and further once the RCD is open there’s good chance the bulk of discharge will mostly divert to a lower impedance path elsewhere.
An RCD does not protect against a voltage surge.
Actually, I’ll expand upon that.
Surge suppression devices are tested with a voltage waveform with an 8 μS rise time and a 20 μS fall time.
A MOV will operate (clamp) in around 10 nano seconds.
A SASD will operate (clamp) in around 10 pico seconds.
A RCD, even if it detected a voltage spike – and it probably won’t – takes somewhere between 2 to 5 milliseconds to open. So basically there is about 6 orders of magnitude difference in the timing of operation between a MOV and an RCD. 9 OoM if you’re talking an SASD.
Even if an RCD did detect and open, the horse has just bolted, it has died of old age.
the horse hasn’t just bolted, it has died of old age.
fixed
>Even if an RCD did detect and open, the horse has just bolted, it has died of old age.
you’re assuming a singe pulse and that the single pulse is a or the fatal pulse.
Is the SASD a one shot gun or can it be reset?
Dropbear said:
Is the SASD a one shot gun or can it be reset?
Doesn’t need any resetting. It sits there and clamps any voltage spike, and then waits for the next one, ready to pounce :)
Saying that, if you get a lightning strike very close by, it will be toast, but so will any other surge device that you mount in your panel board.
sibeen said:
Dropbear said:
Is the SASD a one shot gun or can it be reset?
Doesn’t need any resetting. It sits there and clamps any voltage spike, and then waits for the next one, ready to pounce :)
Saying that, if you get a lightning strike very close by, it will be toast, but so will any other surge device that you mount in your panel board.
That’s fine that’s what insurance is for
perhaps worth mentioning is that other loads (particularly low impedance loads) on the line tend to offer some protection to higher impedance loads, so if the bar heater and the fridge are running, or for that matter those down the street operating on the same phase, these all tend to share and damp spikes like lightning.
http://en.wikipedia.org/wiki/Lightning
Re-strike
High-speed videos (examined frame-by-frame) show that most negative CG lightning flashes are made up of 3 or 4 individual strokes, though there may be as many as 30.
Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds, as other charged regions in the cloud are discharged in subsequent strokes. Re-strikes often cause a noticeable “strobe light” effect.
Each successive stroke is preceded by intermediate dart leader strokes that have a faster rise time but lower amplitude than the initial return stroke. Each subsequent stroke usually re-uses the discharge channel taken by the previous one, but the channel may be offset from its previous position as wind displaces the hot channel.
http://en.wikipedia.org/wiki/Residual-current_device
To prevent electrocution, RCDs should operate within 25-40 milliseconds
transition said:
http://en.wikipedia.org/wiki/LightningRe-strike
High-speed videos (examined frame-by-frame) show that most negative CG lightning flashes are made up of 3 or 4 individual strokes, though there may be as many as 30.
Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds, as other charged regions in the cloud are discharged in subsequent strokes. Re-strikes often cause a noticeable “strobe light” effect.
Each successive stroke is preceded by intermediate dart leader strokes that have a faster rise time but lower amplitude than the initial return stroke. Each subsequent stroke usually re-uses the discharge channel taken by the previous one, but the channel may be offset from its previous position as wind displaces the hot channel.
http://en.wikipedia.org/wiki/Residual-current_device
To prevent electrocution, RCDs should operate within 25-40 milliseconds
Onty, you’re flogging a dead horse. If you get a lightning strike very close to your property, you replace the switchboard and all household appliances. Go direct to insurance company, do not pass go.
For a general run of the mill voltage spike an RCD will do SFA. As I pointed out earlier they are orders of magnitude way to slow to do anything, even if they opened under a voltage spike condition, which it probably won’t as it’s not designed to.
question has been pretty much answered and we can at least agree to ignore sibeen cause he’s a stupid head.
Thanks Wookie, the Wise.
>you’re flogging a dead horse
maybe, but you don’t know for sure that an RCD wont afford any protection from lightning restrike, or any like pulses in which case some preceding strike produces enough difference between A&N to trip it.
I think in some cases it may possibly limit damage, given the reaction time of an RCD is quicker than the typical periods between restrikes.
sibeen said:
wookiemeister said:
I would call the local power authority and get then to get the “ voltage regulation “ team to look at the voltages in the areamy bets are they already know what the problem is and its an expensive fix
My guess is that they couldn’t give a rats as the power they provide is with specification. Believe me, the specs are fairly wide :)
transition said:
>a high voltage spike from lightning may easily bridge that gap created by an opening RCD
>they can’t be used for surge protectionexcept they are every time they operate and detect any substantial difference of current between A&N, which need not be leakage to earth, as for the break current max and flash over voltages still these is not unsubstantial in RCD devices I wouldn’t have thought, so likely having an RCD inline before a voltage clamping device would be helpful. Lightning need not be one fast pulse either, it can be multiple that vary in intensity, and further once the RCD is open there’s good chance the bulk of discharge will mostly divert to a lower impedance path elsewhere.
11,000 volts would easily jump 30cm
you want an ups for the house. might as well go solar with batteries.
I’ve met a man zapped by 11,000 volts
he had his watch on and had opened a cubicle with 11,000 volts on the cables
ok the spark jumped from one phase to the other (and probably earth by then) but the fact is high voltages will bridge gaps much smaller than 30cm
his face has had massive skin reconstruction – my guesses are they kept him around as a warning to the others who all work with HV
do this and this happens
as it is the cubicles were all locked and required a special key
as a general rule if you are in any industrial environment locked places usually signify someone has been killed or seriously injured by entering them without permission. I used to have a key that allowed me access to transformers in the street but I wouldn’t have accessed them without permission because if something goes wrong you look like an idiot.
stick to the protocol
>the voltage spike from lightning would easily bridge a tiny gap
11,000 volts would easily jump 30cm
Well, getting up around and well-exceeding couple KV on the house wiring wouldn’t be unusual ol’ would expect.
I’ve had lightning hit a SWER line not far from the farm house and heard it crack in the meter box(it’s on the bedroom wall).
The other’s house (when she was younger) lightning hit the SWER line near the house, popped the oil out the top of the transformer, put a short on the line, of which ETSA were glad to be informed of, saved them much hunting down, also burnt the telephone cable off the wall.
And I doubt 11kV will start an arc at anywhere near that distance in typical air, or even when raining. Ol’ could be wrong.
ive met another bloke who had been working near a large LV distribution panel in a sub station
unknown to him an errant bolt had been left balanced on the top of the panel
as the board had been nudged it had fallen between two phases and exploded, I could barely make out the injury but he kept his face out of the sun and wore sun cream religiously
this seems a common theme
at the power station an operator by passed the safety mechanism that required a panel to be de – energised before it could be opened
he had filled out his take 5 and then used a tool to prise the safety lock out mech so the panel would be able to be opened – unfortunately for him a piece of metal from a mechanism flew out and landed between the phases whilst live with his face peering into it, he didn’t suffer any injuries – just shock of the explosion. when I got in their smoke was still swirling around the room. when the managers got there everyone was kicked out so they could manage the situation – the real story had already leaked by the time they got there so they were fucked.
transition said:
>the voltage spike from lightning would easily bridge a tiny gap
11,000 volts would easily jump 30cmWell, getting up around and well-exceeding couple KV on the house wiring wouldn’t be unusual ol’ would expect.
I’ve had lightning hit a SWER line not far from the farm house and heard it crack in the meter box(it’s on the bedroom wall).
The other’s house (when she was younger) lightning hit the SWER line near the house, popped the oil out the top of the transformer, put a short on the line, of which ETSA were glad to be informed of, saved them much hunting down, also burnt the telephone cable off the wall.
And I doubt 11kV will start an arc at anywhere near that distance in typical air, or even when raining. Ol’ could be wrong.
beyond 1000V you have working distances because of jumping arcs
beyond 1000V there is no PPE, you just follow the protocol or you are toast
>you are wrong, it happens very easily
there’d be insulators and lightning spark gap protectors on power lines lit up all over the place.
transition said:
>you are wrong, it happens very easilythere’d be insulators and lightning spark gap protectors on power lines lit up all over the place.
I was being told about a particular transmission tower being prone to being the entrance/ conduit point for lightning strikes miles away
actually come to think of it
ive met someone who has had a phone to their ear and the phone line zapped him as lightning hit somewhere else, the earpiece exploded?
Thought this was interesting, not sure how it applies to air with humidity.
http://en.wikipedia.org/wiki/Paschen%27s_Law
“Paschen’s Law is an equation that gives the breakdown voltage, that is the voltage necessary to start a discharge or electric arc, between two electrodes in a gas as a function of pressure and gap length. It is named after Friedrich Paschen who discovered it empirically in 1889.
Paschen studied the breakdown voltage of various gases between parallel metal plates as the gas pressure and gap distance were varied. The voltage necessary to arc across the gap decreased as the pressure was reduced and then increased gradually, exceeding its original value. He also found that at normal pressure, the voltage needed to cause an arc reduced as the gap size was reduced but only to a point. As the gap was reduced further, the voltage required to cause an arc began to rise and again exceeded its original value. For a given gas, the voltage is a function only of the product of the pressure and gap length. The curve he found of voltage versus the pressure-gap length product (right) is called Paschen’s curve. He found an equation that fit these curves, which is now called Paschen’s law…….
……This is 327 V in air at standard atmospheric pressure at a distance of 7.5 µm. The composition of the gas determines both the minimum arc voltage and the distance at which it occurs. For argon, the minimum arc voltage is 137 V at a larger 12 µm. For sulfur dioxide, the minimum arc voltage is 457 V at only 4.4 µm.
For air at STP, the voltage needed to arc a 1 meter gap is about 3.4 MV. The intensity of the electric field for this gap is therefore 3.4 MV/m. The electric field needed to arc across the minimum voltage gap is much greater than that necessary to arc a gap of one meter. For a 7.5 µm gap the arc voltage is 327 V which is 43 MV/m. This is about 13 times greater than the field strength for the 1 meter gap. The phenomenon is well verified experimentally and is referred to as the Paschen minimum. The equation loses accuracy for gaps under about 10 µm in air at one atmosphere and incorrectly predicts an infinite arc voltage at a gap of about 2.7 micrometers. Breakdown voltage can also differ from the Paschen curve prediction for very small electrode gaps when field emission from the cathode surface becomes important”