Not all K&T is un-grounded, often you open the wall and find that it is, and still intact, or had been grounded to plumbing as was allowed right up to 1993.
It's very rare to see grounded K&T in these parts, and the grounding we've seen is questionable at best.
If the customer is not adding insulation, or load, or requires a ground for a specific reason - why replace one 15a circuit of X amount of load for a new circuit with X amount of load with an unused EGC? If they have the walls open that is one thing, but if not that is an unnecessary multi-trade change order IMO. If you were to say go price a service up-grade here, and also demand that the customer re-wire the whole building due to the presence of K&T, you: 1.) May not get the job. 2.) Could be explaining to the license board as to why you're pushing for unnecessary work. Who may or may not see it as justified as you thought it was. If the customer wants it changed, that is another story - but you can't force it upon them unless there is a reason.
In this area, there are no insurance brokers who will insure for K&T, period. You sell your home, the insurance broker gives the new owner has 60 days to replace the K&T. The brokers are even phoning people they insure who live in older homes if they have K&T. Once they know about it, it has to be changed. Now they're starting to request for verification letters from a certified EC that there is no K&T wiring in the home.
It's not a case of the ECs forcing the issue here just to drum up more work, it's the insurance underwriters. We hate doing re-wires, but it's become a necessary evil we have to deal with. There's obviously a reason why the underwriters consider K&T to be such a high risk.
