Isolated system

[skyline1977]

in the UK which electric socket is used with an isolation transformer? since the normal socket has a grounding.
Are there Isolated Ground UK type electric socket

 

[itsmoked]

Umm. Isolation usually means the 'power' is isolated. Not the grounding.

Typically a transformer will be used to keep the source power on one side and a "separately derived source" on the other side of the transformer. Grounds are still required.

In the USA system you must also pick some logical point in the "separately derived" or "isolated" system and physically ground it to prevent any part of the entire system from floating. Floating could cause crazy high voltages to appear with respect to the earth. That can lead to insulation failure as, say, a 200V system wired with 300V wire floating to 400V for some reason, and having the 300V insulation fail.

Someone will be along to tell us if you need to ground part of your UK system.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

In Canada we used to have "Isolated ground" systems.
The grounding conductor for data handling equipment was kept separate from the normal equipment ground conductor used to ground raceways and junction boxes.
Normal receptacles have the ground terminal connected to the mounting strap.
As well as a ground conductor connected to the ground terminal of the receptacle, there was a redundant connection to ground with the mounting strap contacting the grounded outlet box.
In an "Isolated Ground" system, the ground terminal of the receptacle was isolated from the mounting strap.
The raceways and outlet boxes were grounded in the normal way.
An additional grounding conductor was run to the receptacle ground terminal.
These receptacles may be identified by the orange color.
As far as I know the isolated ground practice has fallen into disuse.
Does anyone have recent experience with IG systems and receptacles in North America?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

There are number of UK socket variants with round or T-shaped earth pins, or earth pins rotated 90° from their normal orientation, but none of these have a purpose defined in regulations - they are special-purpose types used for purposes defined by the user.

It's not clear from your question what you are trying to achieve, but you should at least consult BS 7671 and fully understand the UK's Electricity at Work Regulations before designing your system.

 

[dpc]

Bill,

I still see isolated grounding receptacles used in the US, but it's not common. The ground pin in the receptacle is isolated from the receptacle itself and requires ground wire run back to the "source". But usually it it just an insulated wire run back to the panelboard. NRC allows it to be run all the way back to the transformer neutral, but it's not required. The theory is that it reduces electrical noise. It definitely must be grounded at some point. It is simply isolated from the metal frame of the receptacle. Mostly an overpriced product in search of a problem in most cases.

Cheers,

Dave

 

[waross]

I suffered those things back in the 70s and 80s.
When data folk started putting POS registers tied back to a central computer into old structures built in the 40s and 50s, they had a lot of trouble.
Many of the data paths used a ground return.
The data folk didn't realize that grounding was a work in progress in the years when the structures were built.
Many of the early grounding system had a tendency to lose continuity over the years. Armoured cable with aluminum armour was the worst.
It had a strong tendency to become a high resistance, high inductance path.
The data folk's solution?
Isolated ground plugs.
The reality was that by the time the isolated ground plugs arrived, grounding methods had improved to the point that a good code ground was as effective as an isolated ground.
We had a foreman with a talent for making a code ground look like an isolated ground.
As long as the data guy thought that he had an isolated ground it worked perfectly.
A typical conversation, after the installation of a code ground that looked like an isolated ground:
Our guy;
"How important is the isolated ground?"
Data guy;
"Oh, it's very important. I can tell that you have done a good job on this isolated ground by how well it's working."
Even as the isolated ground receptacles were coming on the market, the better equipment was no longer using the building grounding system as part of the data path.
I like your sum up:
" Mostly an overpriced product in search of a problem in most cases. "


Bill
--------------------
"Why not the best?"
Jimmy Carter