Paul,
My construction pricing knowledge gives a rule of thumb that a pure Labour / Materials split is generally 40 / 60, whereas with plant the ratio is closer.
As you say, you have included $1,300 worth of additional materials and assuming your bill includes GST the actual bill for wiring your car equates to $6,200 ($7,500 - $1,300 - $563 (GST))
LABOUR:
Using the rule of thumb assumption the labour component amounts to $2,480.
Electricians rates do vary, but it would be safe to say that $80 per hour is at the top end of what they would be asking.
Based upon the above you would be looking at 31 hours labour or approx 3 to 4 days work.
Does that sound about right with regards to how long the vehicle was being worked on?
MATERIALS:
Ignoring the $1,300 of additional equipment you provided, the materials component equates to $3,720.
This is the area I would be looking at and as Bern says you need to get him to itemise the materials.
Concentrate on the major items and then simply add on 10% for ancillary materials (tape etc etc).
Good luck mate
