Electrical Safety - Please Help

[AHarris]

I am rubbish at electronics yet paranoid about safety.
With my ROV I shall be working with high currents and when you consider 0.5 Amps can kill and the battery has to supply a minimum of 7 Amps to supply motors and lights.... I don't want to be starting any fires or even worse, injuring myself or anyone around me.

What can I do to keep these risks down to a minimum?
I am using Block Connectors that are rated for 15 Amps, and I am using electrical tape (no idea what rating it is at, or even if electrical tape is rated). Providing everything is insulated, should it be fine?
For power to the motors, all power goes into one line and then is sent in what I believe is series to the switches. Then the power goes to the motors.
Is this safe to send it all through a single line?

Thank you in advance for replies.

[fluffy111]

If you insulate it very well will be fine. If you need 7A be shure that you got source (batterie) that can provide at least 10A. In that way you can prevent overheating.

Regards
Fluffy

[AHarris]

Ok, thanks for the tip.
It is 6/7 Amps which I need (as the motors take about 3 Amp/Hours each).

[Silver dollar]

It is safe to handle 12V. You can touch the battery poles at the same time with both hands. It's the voltage that goes through the skin.

[AHarris]

That's something my teacher could never explain... so you can have a large current (which is what kills) but if the voltage can't 'push' it through the skin then it doesn't matter?

Thanks for that help!

[DianneB]

Electrical safety is part of my day job (protection of people and equipment at the power company) so maybe I can shed some light.

The danger with electricity is when current flowing through the body disrupts the electrical signals to the heart. How much current it takes to cause problems depends on the individual's medical condition, the wave shape of the current - DC is the safest - and the path the current takes through the body but 5 milliamperes is usually considered the maximum allowable (that's 0.005 Amperes) and fingertip-to-fingertip or fingertip-to-feet is the worst possible path.

The human body has resistance so how much voltage determines how much current will flow. Legally anything below 32 volts DC is considered safe (32v/0.005A= 6400 Ohms). Most people measure between 47000 Ohms and 470,000 Ohms fingertip-to-finger-tip so are quite safe at 32 volts because not enough current will pass through the body to cause a problem.

With an ROV power source, the first line of protection should be isolating the ROV power from any ground/earth connection (like the powerline or the ship's hull) - that eliminates any fingertip-to-feet danger. Fusing the ROV power at the source eliminates most of the hazard from hot wires or arcing.

If you are working with an ROV power source greater than 32 volts, the power system REALLY should be assessed by an expert in the power/safety field to ensure you (and any spectators) are well protected from any electrocution hazard. There are too many hazards, possible configurations, and methods of protection to give any general rules.

[AHarris]

Thanks for the help, you certainly have helped a lot and you haven't baffled me with technical terms e.t.c. (such as some Safety reports I have read online).

[SoakedinVancouver]

And if you handle any voltage with an open wound (and giving electricity access to that salty fluid running through your body and known as "blood") you are NOT being safe at all.

[tristanplaysguitar]

I'm no expert, but fuses are very important as well. If you're ultra paranoid use more than one, or have a main fuse that cuts power to the system in the event of a short circuit. This will help prevent electrical fires. Good luck,

Tristan

[AHarris]

Good idea Tristan, I was planning on adding a fuse anyway.