Bought a power strip with red and green lights to indicate if it was earthed or not. Although plugged in a socket with a functional earth , the red light ( off ) glowed.

Yesterday, as the live and neutral was reversed to the kitchen plugs ( not by me ), I reversed the wires to correct that, and now the green light ( on ) glows.

Considering that I did not touch the actual plug into which the power strip goes, I am at a loss to explain why the change in the on/ off function.

Perhaps some expert can explain it to me- thank you if you can.

Correct polarity should be L to N 220V, N to E O volts and L to E 220V. Make sure that your protective earth conductor is intact.

The green light should indicate correct polarity, the red light incorrect. Check the documentation that came with the device.

Maybe not related to your problem but I'll mention it anyway.

I always open up any new power strip before using it just to make sure the internal connections are correct.

One time I found that not only was the L/N reversed but the neon switch was wired in such a way that the power was on even when the switch was in the off position

Maybe not related to your problem but I'll mention it anyway.

I always open up any new power strip before using it just to make sure the internal connections are correct.

One time I found that not only was the L/N reversed but the neon switch was wired in such a way that the power was on even when the switch was in the off position

If the polarity at the socket outlet is incorrect the polarity of the power strip will be reversed.

3 pin socket outlets in Thailand have 2 parallel slots at the socket which are polarised, the wider slot is the neutral. Correct polarity may not be observed as the sockets are not switched and switching is achieved by removing the plug top from the socket, thus breaking the L and N.

Correct polarity should be L to N 220V, N to E O volts and L to E 220V. Make sure that your protective earth conductor is intact.

The green light should indicate correct polarity, the red light incorrect. Check the documentation that came with the device.

Check the documentation, LOL. It is incomprehensible, obviously translated by someone that does not speak English properly.

Thanks for all the replies.

Maybe not related to your problem but I'll mention it anyway.

I always open up any new power strip before using it just to make sure the internal connections are correct.

One time I found that not only was the L/N reversed but the neon switch was wired in such a way that the power was on even when the switch was in the off position

I now take a circuit tester to the store to check that all the earths work before buying it, as I bought a strip that not only had a plug that was broken, but no earth socket connections. Saves having to take it back later.