terminoligy clarification

[JACKC]

Can someone clear up my interpretation of floating voltage / floating earth please. I am so confused I can't even write my views down. Tried google but to no avail.
TIA

 

[ricicle]

If an earth from a secondary supply is not connected to the primary supply earth then it can be considered 'floating' ie not 'tied' down so there could be a significant voltage between it and 'true' earth.
This will be the same for the power output as well. If the secondary side of atransformer is not referenced to earth is could be considered a floating voltage.
eg a control tx 240/110 has the primary Neutral bonded to earth. If the secondary 'Neutral' is also bonded to earth then the voltage between the secondary ' line' and earth will always be 110v (disregarding other factors)
If this were not the case then the secondary 'Neutral' could have several volts difference between it and earth and the secondary ' line' not have 110v to earth.

 

[ericmark]

As to floating earth this is what is referred to as IT system and not permitted in UK.

As to floating voltage this is what we have in the output from a shaver socket and any other transformer with the

Isolation sign

• ericmark
• 12 Mar 2009
• 10

symbol and it means the output is isolated from the input and it is not tied to any other item.