Zip Ties: Maximum load?

Just curious, I've been searching but to no avail. How much weight would a zip tie be able to hold? Right now I'm going overboard and over-securing things, but it'd be nice not to waste.

Thanks

I think it just comes down to common sense. I wouldn't go over 15 lbs. You could do a test?

depends on the size and kind there are big suckers i can hang my 250lb ass from.

the big ones that come in an asort pack are like 9inch and will hold 20lb but double or triple up just in case

Thanks guys. Yeah, I could test it, I was just wondering if there was anything 'official'.