On what basis do you suppose thye rate this at 13 amps, instead of the
usual 15 amps for 14 gauge? The length? 100 feet

http://www.lowes.com/pd_59610-66906-...&CAGPSPN=p la

Their 12 gauge gets rated at 15 amps.

http://www.lowes.com/pd_67439-16503-...&CAGPSPN=p la