We have been working with DC Furnaces for several years. Arcing will never be totally eliminated, however it can be reduced to a point where operation is reliable.
Do you have some findings on how the roof panel was damaged?
The solution is a little bit complex to be explained but I will try.
Beginning with the power supply, it has to be "floating", the P and N bus should not be solidly grounded. They are grounded through a resistor array. The reason is to let either the P or the N bus to touch a grounded...
I might be able to help you. We have two dc-furnaces running without this problem. The solution is based on the type of anode you have. Please inform which type you have.
