Voltage Tests

[jsmmonaco]

good morning............dumb question time.............can someone give me a basic lesson on circuit testing?..........I have never really messed with anything electric, and I would like to know what to do, or not do, so I don't get a surprise....................I have always paid for this type of stuff in the past, but looks like owning an rv will require some level of electric testing knowledge..........thanks

[lostinfla]

First rule...Don't touch anything that's shiny metal. Seriously though, get a good meter and ALWAYS check for voltage before you get your hands on any electrical device. 110 volt ac, white is neutral, green is ground and black, red, blue, etc. is hot. Don't ever work on a circuit hot unless you absolutely have to. 110 can kill you in the right situation. With dc voltage (12 volt), black is usually ground and the other colors are hot (again, usually). Some manufacturers use what ever color they happen to have, so again, check with a meter to verify polarity. You can pick up a book that will show you basic circuits and trouble shooting methods if you are half way mechanical. JUST BE SURE TO CHECK FOR VOLTAGE, EVERY TIME!!

[l1v3fr33ord1]

Hello jsmmonaco-

You've tossed out a big question, and as there are many "professional" and self-taught electrical folks on this forum, I hope you'll get better answers than mine. But let me ask a few simple questions first:

1) Do you have a specific problem that you'd like to solve right now? If so, give the details as best you can. Working on your immediate problem is a great way to learn.

2) How do you learn? Words, diagrams, pictures, movies, sounds, analogies can all be used, but you will have a preferred learning style. The Web is full of "help" of all kinds, but sifting through it to get to what you need is the hard part.

3) Do you like to work with your hands, and can do it well (enough) in other areas, like carpentry?

4) Do you have a technical background?

5) Do you have a healthy sense of self-preservation? Even 12-volt circuits can seriously hurt you, and 120-volt circuits can kill you.

That said, here's testing in a nutshell:

Power source ---> fuse or circuit breaker ---> wire ---> switch (optional) ---> wire ---> device

A voltmeter or test lamp inserted in the various places marked with "--->" above will often reveal the problem cause.

Now, the details on the problem at hand are...?

Mark

[zmotorsports]

This is quite a broad and open ended question. Voltage tests can be referenced as to testing for voltage, testing for ground or voltage drop tests.

Then the next question would be are you testing the load or a control circuit such as when a relay is used. There is some basic terminology to be used and explaine to go along with testing.

As others have already mentioned testing incorrectly can be dangerous due to physical injury but not knowing what components do what and touching something with a test lead can sometimes cause more expense and damage to a component.

It may be more helpful to give an actual example and we can walk you through the basice test or tests for that situation.

Mike.

[Mike Canter]

For a 12 volt system a 12 volt test light can be a great help. For 110 v you need a digital volt meter/multimeter which also tests resistance and helps find bad connections. You can't get hurt with 12 volts but you can weld watches and wedding rings to contacts and that can result in a burn because the metal will get hot real fast. With 110 volt AC only use one hand at a time and hold the other hand not being used behind your back. This way if you get across a connection it will not pass from one hand to another across the heart. That safety rule allowed me to survive 26 years in the Navy. If you go to Home Depot and look in their book stand you will find some very good books on explaining AC wiring and testing.

[walt2137]

I think if you would go to this link it would also help. And check out the Progresive EMS-HW50C this unit is a must for rv protection.
http://www.irv2.com/forums/f115/50-a...er-176562.html

Walt

[wa8yxm]

It all depends on what you are testing.. If you google NO SHOCK ZONE you will find a lot of information but here is some

As someone up-thread said DO NOT TOUCH METAL EVER, when running these tests

50 amp outlets have 4 holes 3 flat one roundish.

With the roundish hole at the bottom the sides should measure 220-240 volts side to side

110-120 side to center and side to round

ZERO top to bottom (Round).

On a 30 amp you have two flat and one round.

Round to one flat 120 volt Side to side (flat to flat) 120 volt,, Other flat to round ZERO.. I'm not sure without testing which side is zero.

12 volt side of life

about 12.6 is the resting voltage of a fully charged 12 volt battery, Put a load on it and it goes down

13.6 is a common "Float" voltage and what you should see if batteries are charge and you are plugged in.. Alas, I almost never see it but I'm not reading AT THE BATTERY or CONVERTER and there are loads present when I'm reading.
14.6 is a common boost voltage (Lots of variation here)

Less than 10 is trouible. (less than 12 is trouble)

Other systems.. Need system spec.

[jsmmonaco]

thanks to all that have responded..........lots of good information.....nothing needing repaired at this point, but one never knows..............I think I will leave the electrical repairs to professionals....................

[wa8yxm]

One of the problems I have is that I've been doing electrical/electronics work for a LONG time (personal, not professional) It is easy for me.

But one thing I forgot to say above is test lightes are often better than meters for working on circuits.. Epically 12 volt.

With the light you have 3 conditions BRIGHT = GOOD (volt meter would agree)
DIM = Bad connection (Volt meter would (did in my case) show good)
Dark = Dead (volt meter should agree but again might show good) if DARK= Extreme Dim (Did in my case)