die-electric protection

[rgrier 819122801]

when and why do i need

[NormChris]

Your question is not clear. A dielectric is just another name for insulation. Plastic insulation on a wire is a dielectric. The insulation between the two plates of a capacitor is a dielectric. What exactly are you asking?

[rgrier 819122801]

when going from copper to brass to steel pipping do you need a die-electric the brass and steel

[NormChris]

Yes, you use a dielectric coupling. It is a coupling with insulation in the middle so the two dissimular metals do not come in contact. When two dissumular metals touch a small voltage is generated and this in turn causes a small current. The result of this is electrolysis or basically the same thing as occurs in electroplating. In this case we call it corrosion.

[rgrier 819122801]

copper to brass no prot need .steel to brass no prot neededtherefore would the brass act as protection in copper ,brass,steel run

[NormChris]

Each combination of dissimular metals in contact produce electrolysis to a different degree depending upon the combination of metals involved.

I see you are a pipefitter by trade. I bet you have a pipefitting book that will give you an exact answer for the combination you are using. Frankly, I don't have a more specific answer for you. I know in gas fitting we fit brass and copper to black pipe without a dielectric coupling without any problems. But, water in the pipe instead of gas may change that.