What is the difference between the two? I often saw them used interchangeably until a while ago

If you must use two metals farther apart than 200mV, you need to take steps to protect them, either by insulation or isolation (so they're not in contact) or by using anodes.

If someone knows to explain on a practical example?

  • 2
    Have you considered looking up the definitions on-line?
    – Mitch
    Dec 13, 2011 at 0:31

1 Answer 1


The example sentence uses sense 3 of insulation, "...separating a body from others by nonconductors, so as to prevent the transfer of electricity..." and sense 1 of isolation, "state of being isolated, detached, or separated".

Electrical isolation amounts to using an air gap (or vacuum) as an insulating (nonconducting) medium; like most electrical insulators, air has a breakdown voltage, typically about 1000V/mm, while the breakdown voltage in partial vacuum may be substantially less.

  • So, if I may, "insulation" would be wrapping the wire in thick plastic, while "isolation" would be separating the wire from anything outside wishing it "harm"? To put it bluntly.
    – Rook
    Dec 13, 2011 at 0:22
  • Yes, if the plastic is nonconductive, which usually is the case. "Insulating" typically means using a tangible barrier to reduce conduction, while "isolating" means separating by a distance suitable for the voltages involved. Dec 13, 2011 at 0:30
  • @Idigas: I think it would be more appropriate to say that "isolation" is separating it from other electrical components, regardless of whether there's any harm involved.
    – Lynn
    Dec 13, 2011 at 5:11

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