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Can too many cheap Christmas LED lights cause problem?

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wilykat

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Not the wifi issue, the power grid. Some of the cheap LED string are only half wave rectifier and if somehow someone stings up hundred thousands all exactly the same way, that seems to result in drawing several amp of power for 1/60th of a second, no draw in the next 1/60th of a second, and back n forth. (1/50th in European countries I guess)

Could those be an issue? I doubt anyone saw this when the power grid was designed over 100 years ago.
 
Hi wily,

You are quite correct; drawing unbalanced current from the mains supply is not allowed, in the UK anyway. But have no fear the power that a single string of LEDS takes would not cause a problem. If there are hundreds of thousands, then there would also be hundreds of thousands of mains grid circuits, so once again no problem.

Untill relatively recently many domestic electrical items were half-wave rectified: mains radios (50W), CRT TVs (200W) and so on.
 
I found some electric water heaters pull power on 1/2 cycle in low power mode. They are TRIAC controlled, can turn on/off at zero crossing. I know this because that drives some typed of power meter crazy.
 
Note to the countries of China and Taiwan - one way to mitigate this is to assign randomly the connections to the power plug.

ak
 
Note to the countries of China and Taiwan - one way to mitigate this is to assign randomly the connections to the power plug.

ak

Good point- can't you do that with any mains supply though?
 
Depends on the device and its safety ratings. Some require polarized plugs and specific connectivity inside.

ak
 
The loads are connected in many houses, on all three phases. Also there is no alignment between the three phases on different transformers, so positive phase on one transformer could well be at the same time as negative phase on another.

The far bigger problem is that lots of loads take most of their current near peak voltage, which results in significant flattening of the peak of the sine wave. Also the third harmonic of all three phases is synchronised.
 
Thks Diver, I'm getting some good info on how it all works :happy:
 
I just checked a number of Christmas tree lights. Some are polarized and some are not.
The polarized lights do not help anything. The first light connects to one plug and the last light connects to the other plug. So trying to force the lights to be only plugged in one direction does not help safety at all.
 
I just checked a number of Christmas tree lights. Some are polarized and some are not.
The polarized lights do not help anything. The first light connects to one plug and the last light connects to the other plug. So trying to force the lights to be only plugged in one direction does not help safety at all.
Yesterday, I was instructed to install the Xmas tree- a yearly ritual. The LED string is a magic thing- about five modes which you can toggle through for differnt effects by pressing a button on the wall-wart. Trouble is, you never know which mode it will start in. Often the circuit gets into a tangle and races through all green, all red and all blue- very disconcerting if you are trying to watch TV, or worse still, if wifey is. The only way out is to reboot by switching off and starting all over again.
 
The only way out is to reboot by switching off and starting all over again.
Windows 10 for Christmas lights.
1)Reboot.
If that does not work:
2)Reload from original CDs.
If that does not work:
3)Reflash the mother board.
If that does not work:
4)Add more memory
If that does not work:
5)Need bigger hard drive:
If that does not work:
6)Up grade OS to newer version.
If that does not work:
7)Upgrade CPU
If that does not work:
8)go to step 1.
By now it is well into February and there is no need for Christmas lights.
 
Windows 10 for Christmas lights.
1)Reboot.
If that does not work:
2)Reload from original CDs.
If that does not work:
3)Reflash the mother board.
If that does not work:
4)Add more memory
If that does not work:
5)Need bigger hard drive:
If that does not work:
6)Up grade OS to newer version.
If that does not work:
7)Upgrade CPU
If that does not work:
8)go to step 1.
By now it is well into February and there is no need for Christmas lights.

:p:joyful:
 
Should meet with your approval wilykat- the lights have a proper PSU :smug::smug:

MZ7A3858_Xmas_Tree_mod02.jpg

 
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