Best Online resources for electrical drawing?

[tigris]

I have used autocad and solidworks mostly for mechanical work, but I have been asked to update some commercial electrical asbuilt drawings. Where can I find the best reference online for understanding symbols and general electrical layout guidelines?
Thanks

[CADken]

check the NEC code books, try the CAD Block Exchange Network for samples and such...

the best thing to do is research some materials related to the electrical field... I know book stores carry reference books for trades, i'm sure they will have something with symbols.