ice on a/c copper line

[midwest]

I have an outdoor a/c unit and ice is forming on my copper line to at least 5' inside the house. The nights have near zero degrees but my gas furnace is working properly. Is this normal or do I have an a/c problem I'm not aware of?

[HayZee518]

not to worry - the temp of the pipe in the houseis warmer than the contents if the pipe so ice forms. I have a monitor heater and inside is keresene but when the temp outside is zero or below I too get ice forming on it. no jarm, the furnace still works.