I'm installing a kitchen that'll have a peninsula and I'm wondering about section 210.52(c)(5) where it says that "…receptacles mounted below a countertop must not be located where the countertop extends more than six inches (150 mm) beyond its support base".
If I've got this kind of situation (the counter is 12" deep): 
can I install a receptacle a few inches in on the half-height wall (so that it's still under the counter, but not a full 12" in)?
Best Answer
Answer based on the NEC in the US:
Yes, that's almost right. As long as you are not more than 6" in laterally off the counter edge you are fine.
Also, the receptacle cannot be more than 12" down from the counter top.