Hi Mike,
From what I recall in EE classes there's nothing in Ohm's law that differentiates between a single multi stranded wire and multiple single stranded wires. From a theoretical standpoint it's all about resistance and/or impedance.
However the real question is whether the wire or the Electrical Inspector would provide the most resistance. As always we suggest that you check with the "authority having jurisdiction" where you live. If you have a professional electrician doing the work and the local authorities will sign off on it knowing how you implemented the system then you're good to go.
If not there's a good chance they'll have suggestions for alternate approaches. We had the best building inspector (until he recently retired) in the town I live in. Not only did he know his stuff but he was incredibly patient and helpful even to DIYers. He never lost sight of the fact that he worked for the taxpayers of the town and that his job was to make sure that they were safe. So he was always willing to come out and inspect things during construction since he always said it was better to get it right from the beginning than to tell someone they did it wrong when they finished.
Try contacting your inspector. You may be surprised at how accommodating many of them will be....
- Jay
