Go to an electrical supply store and ask for panel mount zip ties. They should be relatively easy to find. McMaster is conveinent for me because i can tag them along with work orders so i got them there at the time and don't have to pay shipping. $2 a PIECE!! it is nuts, I got mine for a fraction of that price.

I guess I COULD spare some for you. I'm feeling generous today. Send me an address and i'll stick them in an envelope your way. How many do you need?