This is a good topic, how to avoid problems, with design build projects. When doing design build work, such as your switchgear installation, it is best to have a professional engineer, design, and spec. all the equipment, many contractors, try to avoid the cost of professional engineering, and end up in litigation, when problems arise, and to make matters worse, they are usually not insured, to do design work, which requires professional errors, and ommisions, libality insurance.
On the purchase order issue, that uaually has the customers terms on it, not yours, again, many contractors, are afraid, if they ask to have their contract signed, the customer will find someone else, at this point if they don't want to sign your terms, best to pass on the project, you need protection, and without a written contract your position is weak.
As posted above, you may need to get your attorney involved. "You need his professional opinion as to what your area recognises as to express and implied warranties, damage limitations, etc."
[This message has been edited by LK (edited 11-01-2006).]
