I am not familiar with the Nordic
40 so I don't know if your mast is deck
stepped. I'll answer for both to be of the most help to everyone.
stepped, likely there is some sort of gasket
between your mast and step. But even if there isn't, neither the connection between the mast and step nor the connection between the step and compression
post plate will be adequate.
For keel stepped, definitely ground the mast - you do not want to try to make the current
go horizontally to get it to ground. Also, to be on the safe side you should ground the step.
Any bend in your wires must have a radius no smaller than eight inches.
Use the largest ALUMINUM
lug you can find, be sure the manufacturer states that it is compatible with copper wire, and tap screw holes into the mast (do not rivet the lug to the mast) and fasten it with aluminum
or stainless steel
machine screws. I used two layers of heat shrink to protect the wire and connection from UV and corrosion
. Use an aluminum-compatible anti-corrosion conductive paste between the lug and the mast, and remove the lug and clean and preserve the connection annually to keep it low resistance. Treat the connection to your keel bolt the same, but use a tinned copper lug.
If I remember correctly, ABYC recommends a minimum of 4 AWG wire for your main lightning
conductor ... have you seen the size of a lightning
bolt?! On my boat I used two 2/0 AWG cables
to ground the mast, and also grounded all four step bolts on the compression
post. Probably overkill, but that's the way I do things that matter.
There is another cable just like it on the other side: