Tom, I don't know that hooking the clamp to the negative terminal causes voltage problems, but it's not recommended by the "Experts."

Clamping to the terminals WILL cause a spark when the second clamp is applied, positive or negative. This spark CAN ignite any hydrogen escaping from the battery cells through the breathers. Thus, it's better to make your first connection to the positive terminal, and the second to the frame at some safe distance, at least a few feet, from the battery.

That said, do the voltage transients from the arcing damage the OVR? If so, does it matter where you clamp, or will damage occur anyway? What is the recommended other than jumping, especially if you're stranded away from a good battery charger? Inquiring mind wants to know

BCingU, Jim