Dupla 25W Cable and Electrocution (fwd)


This was sent to owner-aquatic-plants at actwin_com instead of
aquatic-plants at actwin_com.


Shaji Bhaskar, Durham, North Carolina                   shaji at nando_net

---------- Forwarded message ----------
Date: Wed, 6 Mar 1996 10:26:06 -0600
From: chapman at SEDSystems_ca
To: owner-aquatic-plants at actwin_com
Subject: Dupla 25W Cable and Electrocution

Despite assurances that Didi received from the guy at the pet store, I'd still 
have "grave" concerns about running the 120 V heating cables in my tank:

> the guy told me not to worry about it since the cable has a grounding wire 
> right along and that in case of failure the path of least resistance will 
> be the ground just in case that doesn't work, the wire has a fuse that will 
> blow really fast should the electric current choose the body. "After all, 
> people put powerheads in their tanks all the time"

In the first place, electricity does not just take the path of least 
resistance -- it takes every available path.  You can see that this is true 
from your own experiences -- you can plug several different items into a 
power bar, and electricity flows into all of them, even though each has a 
different resistance.

The purpose of the ground wire is to make a low resistance path to ground 
available so that if a fault occurs, a large current will flow and result in 
a blown fuse or circuit breaker.  If the cable has an internal fuse, as the 
salesperson implied, that is its purpose.  No fuse can tell if current is 
flowing through your body or not.

It is possible for a fault to occur that would only allow a little bit of