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Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

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RE: Why would reversing AC leads reduce hum in a component?

Posted by jea48 on February 11, 2017 at 21:33:23:

You're talking nonsense about the UK system and its 3-pin plugs.

Really? Why don't you enlighten the class with your vast electrical knowledge.

I would love hear your thoughts on why in the UK the 2 conductor power cord of a double insulated Class II piece of equipment or appliance uses a 3 wire grounding type plug as you have said.
Could it possibly be the reason I gave in my last post? The ground prong on the plug only allows the plug to be plugged into the receptacle one way. It maintains the proper AC polarity orientation of the plug to the AC polarity of the receptacle.Surely you understand that?

No point in pursuing either it or what is meant by "double insulated".

What do you think "double insulated" means?

Class II
Class II symbol

A Class II or double insulated electrical appliance is one which has been designed in such a way that it does not require a safety connection to electrical earth (ground).

The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having at least two layers of insulating material between live parts and the user, or by using reinforced insulation.

In Europe, a double insulated appliance must be labelled Class II or double insulated or bear the double insulation symbol (a square inside another square).

https://en.wikipedia.org/wiki/Appliance_classes