Watts per square inch?

So I am continuing my research on home depot regarding my evential electric HLT and BK builds. With only access to a 120v outlet, I am leaning heavily toward a 2000w element, but on home depot the other day, I saw this jawn:

http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

it says 50 watts/squar inch. I'm confused. What is the voltage required? What would the wattage be if used for full volume boils in a 40 qt aluminum HLT? Would this heat a full volume 5 gal batch? Could I use it on a 120v outlet?

Many questions, and for that I am sorry! hahaha, Thanks for the help!

50 W/in^2 is the power density. Without knowing what the surface area of the stupid thing is, or if 50 W/in^2 is at 120V or 240V, we can't know how many watts it'll pull in total on a 120V circuit.

Googling around, I can't find that information either...50 W/in^2 is pretty low wattage density, (I THINK it qualifies for ULWD, don't quote me)....based on the size of the thing I'd hazard a guess that it's a 240V element, (13" long is pretty big for a 120V one...), but as to what the actual wattage pull would be at 240V, (thus allowing you to figure out what it would be at 120V), I have no idea...

Based on hunting around for Limelife elements on Camco's site, and assuming it's either a 11 or 13" element, (because it says minimum tank diameter 14", and they always leave at least 1" of space between element end and tank wall), it's either a 2500W or 3500W 240V element. At 120V, this translates to 625 or 875W. If it's the 14" 4500W 240V element, then it's gonna be 1125W at 120V. If it's the 14" 5500W 240V element, then it's gonna be 1375W at 120V. Camco only has 240V elements in foldback incoloy elements listed on their website, so it has to be one of those three, ASSUMING camco's website is up to date, and honestly it looks pretty sh!tty.

Edit, nevermind, found one 120V incoloy element...a 12" one rated at 1500W at 120V.

Good place to buy and research http://www.plumbingsupply.com/elements.html