I will get back to my motor vehicle systems ramblings ... I promise. When I do, I'll resume where we left off -- starting versus deep-cycle batteries. It may be a while ... payday was a few days ago, we made one of our occasional trips to town yesterday for supplies, it's warm and sunny outside, and I have the materials I need to resume work on some of my projects.
One of the reasons I'm writing this now is the dog managed to land on my bad leg last night, causing me to wake up and, in turn, waking up my wife because of my loud scream of pain. That, combined with my service-connected mental health and pain management issues, has made it difficult to get around to doing anything today involving physical movement. (Some days, the only thing I manage to accomplish is putting away a single thing.)
The other, more important reason is a member of our group has been messing with a 120/240VAC electrical system. That makes this a very good time to discuss safety.
This is information is repeated all over the place. However, some people somehow manage to avoid reading the warnings and, worse yet, some people overlook or ignore them. (I will admit I sometimes unintentionally violate the same warnings.)
I'm not really superstitious but, when it comes to electrical work as well as firearms, I do believe in PFM. (Pure F'ing Magic.) As soon as I pick up a firearm, I clear it. (This got me into trouble in basic training ... personally, I would have given the students a demonstration in clearing a weapon before telling them to pick theirs up.) Even then, I tend to clear the weapon again, especially if I've looked away or put the weapon down momentarily. Simply put, I tend to believe a round has somehow magically appeared in the chamber. (A small scar on my hand due to a supposedly empty BB gun tends to reinforce this belief.)
My approach to electrical systems work is similar. Even when I know all power has been removed from a circuit, I still approach it as if an electrical current has somehow found its way into the circuit. (Ask one of my friends ... he discovered this when his teen-age daughter turned on all the circuit breakers so she could make popcorn in the microwave. The result was a screwdriver flying across the room, a small bit of fireworks, some blackened metal, and his preschool son helpful pointing out that he was hearing "dirty" words.)
Healthy professional electricians like to keep one hand in their pocket. This is to prevent them for unintentionally using their body to create a short circuit, usually by grabbing a metal ground. For many, this is so ingrained that they automatically go on "high alert" when they have to use both hands. (The wife of one mentioned he tended to tense up when he had to use both hands to prepare food or change the baby's diaper -- the second example may have also been do to the nature of the task.)
I strongly recommend you buy and regularly use an AC voltage detector.
This is one example, although I'm not necessarily recommending this example. I currently don't have one because both of my two previous ones were stolen. (Excuse me, "borrowed." One anonymously and the other never returned.)
I haven't gotten around to getting another because the electrical service to my property is protected by a removable fuse block that I can pull out and keep in my pocket, thus cutting all power to everything I own.
NOTE: I am not implying that 12VDC is any less dangerous than 120/240VAC. Watts is what determines how much work -- or damage -- an electrical current can do, with watts being equal to amps times volts.
So, 150 amps at 12 volts has the same work -- and danger -- potential as that available from a common 15 amp 120 volt household outlet. (For those who haven't been keeping track, this means the current surge going to your engine's starter can be as much as 10 times that coming from your house's electrical outlets.)
