View Full Version : Ripple switch control

effie C
09-05-2003, 09:20 AM
Have just had my tame tutor in for some correctional work- and he has just advised me to pull the plug/switch off at the wall when not using the computer, in case this ripple interferes with it -- any comments?

effie C
09-05-2003, 09:22 AM
sorry that should be ripple switch electric heater control if it is utilised in any power board area

09-05-2003, 09:33 AM
Ripple control signals are in the range of 175 Hz to 1050 Hz, superimposed on the 50 Hz mains. (Most are below 385 Hz)

Voltages are in the order of 0.7v to 3 v typically, so should be "invisible" to a PC power supply, which rectifies all incoming voltages to DC anyway.

Most signals consist of a number of pulses of the higher frequency (about 0.7 seconds of pulsed signal, with about 10 pulses per signal)

It would need to be a VERY dodgy power supply to suffer any interference from a ripple signal. I have never encountered one, and if it were an issue I would know.

I have seen problems in very remote areas of the country, which are supplied by "Single Wire Earth Return" (SWER) 6,600 v systems, where there is a resonance issue and these voltages can get up in the tens of volts additive to the mains, but that is a very very rare situation.

Almost all areas of NZ have ripple signals on the mains.

Billy T
09-05-2003, 09:49 AM
I endorse Godfather's comments.

I think ripple control has also been used for streetlighting control in some areas as well, but apart from the old system interfering with stereo recordings some years ago, I have never heard of any problems with electronic equipment, let alone computers. You used to hear the ripple signal coming from your meterbox many years ago but that is history now. Even though my meterbox still has the old electromechanical resonant switch installed, it seems to operate silently now. Either that or I am deafer than I thought!

Refer your Tutor to this thread for a "Heads Up"


Billy 8-{)

09-05-2003, 10:14 AM
its not a bad idea to turn it off at the switch but thats to help stop spikes comming through not the ripple control :)

Smithie 38
09-05-2003, 10:35 AM
Thats right tweak'e but it also applies to all the electronic equipment in the home.
If you use the normal shutdown switch on your computer, but leave the switch on at the wall, would a spike be a potential danger then, or must the computer be running.

09-05-2003, 10:43 AM
when you turn off the pc the pc still has power running in it so even if its off it can still get spiked. however you are more likly to get spiked up the telephone line than through the power cable, so a good telephone surge protector is very highly recommended :)

Terry Porritt
09-05-2003, 10:51 AM
You can actually hear the ripple control signals come through on some cheap bedside clock radios which have poor supply smoothing.

Smithie 38
09-05-2003, 10:56 AM
Geez tweak'e how can I organise that to happen when mother-in-law is on the phone :D

09-05-2003, 11:22 AM
Ripple control is used extensively for:

Peak load control of waterheaters
Tariff control (day/night meter register changeover)
Night Heating on/off
Signalling of high network load periods for major customers
Price sensitive shedding of load (drops waterheater load when prices are high)

Also some of the later ripple relays automatically drop the load if the mains frequency goes below the allowable limits, and therefore they can be used to provide automated emergency load shedding, which can be useful if a fault knocks a major generator off-line suddenly.

Susan B
09-05-2003, 12:16 PM
> Geez tweak'e how can I organise that to happen when mother-in-law is on the phone

A new cordless telephone for Mothers' Day? :p :D

So how does this ripple control actually work?? Do they send less power through the lines so that the water heating element stops working or something? And how can you hear the ripple control signals coming through?

This is all a great mystery to me, despite having a plumber for a Dad. :D

09-05-2003, 12:34 PM
Godfather - I'm impressed with your knowledge - most people don't know that these things exist.
I have worked for "power boards" and now an asset owner for about 17 years - especially in the metering and load control fields.
As to the worry about a ripple signal damaging anyones PC - there is more chance of your friendly microwave frying it than the ripple signal.

09-05-2003, 12:41 PM
SusanB - the ripple signal is "Injected" onto the normal power supply and is detected by the sensitive electronics inside the device.
If you picture "normal" electricity as a line that "alternates" up and down 50 times a second - the signal "rides" on the "back" of this line at 475Hz in Wgtn and 1042 in the Hutt (not too sure of other areas), and as Godfather has said it is normally set up of decabit binary code (a combination of "ons" and "offs" that make up a block of ten) - this is how there can be heaps of different codes using the same equipment.

Hope that helps a wee bit :)

09-05-2003, 12:45 PM
We've got a night store running which I assume uses the same and it hasn't done affected anything.

From what I've seen the PSU would have to handle a bit of variation any way, actual AC voltage at the outlet varies a bit & the waveform isn't exactly smooth either.

09-05-2003, 01:13 PM
Bmason - thats correct - "Night store" heaters are usually switched on at 11pm and off again at 7am - so as you can see no harm so far - no harm from how on - the biggest threat to pc's will be if any blackouts occur - the peaks and surges that occur when "Power up" can be vicious to sensitive electronics - hence the warnings to turn appliances off when a power cut occurs

09-05-2003, 01:22 PM
I read the other day that up to 50,000 of the controll switches might be faulty and so not let the power prople turn off your hot water. they said that because the hotwater switch is not uses very often a lot of them have get "in to a state of dis-repair".

where is the switch and could a home owner make the switch get "in to a state of dis-repair"???

09-05-2003, 01:28 PM
The "switch" will be on your meter board - next to your meter (or in some cases inside your meter) - and it isn't able to be "corrected" by a home owner - the home owner can ring their retailer and request a replacement due to it being faulty (at no charge).

Billy T
09-05-2003, 03:06 PM
Just to add to that advice robsonde, the hot water pilot wire is always live regardless of the position of your main switch so don't even think about fiddling with it. Even electricians have been caught out by pilot wires and received shocks.


Billy 8-{) :|

09-05-2003, 03:18 PM
Billy - where abouts are you?

Terry Porritt
09-05-2003, 03:27 PM
We used to have one of the older electro-mechanical type off peak ripple control relay thingies on our meter board, the type that used make clacking noises as the wheels turned when the ripple signals were going. It went faulty, and was replaced by the Hutt Valley Energy Board that was, with what seems to be a quiet solid state one. Blast, now we will have our hot water turned off.

09-05-2003, 03:33 PM
Yes those old one of the HVEB were very noisy - mind you at the old Capital Power our Bias relays were pretty much the same.
Is that the Terry from Griffins Darts?

Terry Porritt
09-05-2003, 03:52 PM
No, Nomad, I dont think there are 2 of us with that surname :), ex DSIR/PEL/IGNS.

09-05-2003, 04:50 PM
You could always just wire up the hotwater cylinder with an old extension cord and plug it straight into the wall. ]:)

09-05-2003, 05:10 PM
> I have worked for "power boards" and now an asset
> owner for about 17 years - especially in the metering
> and load control fields.

NGC Nomad??

You may well know me......?

Murray P
09-05-2003, 05:16 PM
What sort of electrician would be fooled by a pilot wire Billy :O

Cheers Murray P

Billy T
09-05-2003, 05:17 PM
Well Nomad, last time I checked I was sitting in my office
here in Auckland. Nice of you to ask :p but is there a reason?


Billy 8-{) :D

[b][pre]If you plan on sending cash I'd just as soon give you my
Swiss Bank Account number where I hide all my graft and
gratuity payments. :O

Susan B
09-05-2003, 05:19 PM
Thanks for that explanation, Nomad, it helps "a little bit", yes. :-)

This elec-trickery is magic stuff really, magic.... :D

Graham L
09-05-2003, 05:31 PM
"What sort of electrician ..."?

A very surprised one. :D

Tom McB
09-05-2003, 05:50 PM
In places where power cuts occur often, these spikes are also common place. Hence, there is a market for "power-on delay" devices that you plug your appliance (say, the fridge) into. The device withholds applying power to the appliance for a set period on the assumption that the spikes would have dissipated by then.

A brand new telly I've given to my folks was actually totalled by a surge after a powercut (back cabinet melted in half) and nearly caused a fire in their bedroom...

09-05-2003, 08:47 PM
Susan B, re your elec-trickery comment. As an ex electrician I can state positively that it is also very painful. Electricity has very sharp teeth. The worst shock you can get is "hand to hand" across your chest, can stop your heart. Scary stuff. Poppa John

Billy T
09-05-2003, 09:10 PM
> What sort of electrician would be fooled by a pilot
> wire Billy :O
> Cheers Murray P

More than one Murray, they look just like any other when you are in a hurry.


Bily 8-{)

Murray P
10-05-2003, 12:27 AM
I had a really clever riposte to that Billy, then the server timed out when I posted. Now this seems like a better idea. :D

Cheers Murray P

12-05-2003, 10:08 AM
Godfather - good guess - yourself?

Terry - the name looked very familar - and I used to play darts with a Terry from Upper Hutt but couldn't remember his name.

Billy T - was just asking - was curious about the "live" pilot system - so no deposits for your swiss bank account

12-05-2003, 11:06 AM
Ever heard of "MARIA" Nomad1?

12-05-2003, 11:16 AM
Godfather - certainly have - pain in the butt is it too

12-05-2003, 11:34 AM
Well, I use gas hot water, so I will think of you all when I have a shower!

(even have thermostat so don't heat then mix with cold, just dial up a temp and use it).
Works well, and is looking pretty good about now. Got gas heating too.

Terry Porritt
12-05-2003, 12:08 PM
Doesnt your gas heating system have electrical control, robo?
Ours did back in UK, so when there was a power cut the gas heating was lost too, also the central heating pumps wouldnt run.
Maybe tough bikkies robo :_|

12-05-2003, 12:18 PM
Yes, but we aren't affected by ripple control turning off water cylinders. As long as we don't have a complete black out we are fine. I suspect brown outs will happen before they cut power completely.
Wonder what they would save if they cut street lighting? You have to wonder why we have it on most highways, or maybe we should just turn off our car lights.

Graham L
12-05-2003, 02:10 PM
The gas won't last long, robo. At least it rains sometimes in the SI. We can always cut that cable.