Page 2 of 2 FirstFirst 12
Results 21 to 36 of 36

Thread: Dumb question but

  1. #21
    Join Date
    Jan 2012
    Location
    Broomall, PA
    Posts
    3,421
    Post Likes
    Quote Originally Posted by RandallJ. View Post
    I just went to trade school but apparently something this elementary is assumed to be known. Dont want to get to work and my lead ask me to check the voltage and i don't know what to do.
    Welcome to the trades. And no offense, but I wouldn't take the 'fake it to you make it' approach to electricity and testing. Knowing you just came out of trade school I would encourage you to ask as many questions as you have. I good seasoned tech should be more than happy to answer them.
    If I do a job in 30 minutes it's because I spent 30 years learning how to do that in 30 minutes. You owe me for the years, not the minutes.

  2. #22
    Join Date
    Jan 2010
    Location
    Sea to Sky
    Posts
    4,708
    Post Likes
    Quote Originally Posted by Sooty View Post
    Exactly. Electricity doesn't care about colour never forget that it might save your life or at least a control board or two.
    X2. A guy I knew from the Philippines told me all the wiring there had black insulation.

    I have worked on racks where all the wiring was red.

    Other units were all the wiring was white.



    Sent from my SM-G965W using Tapatalk

  3. #23
    Join Date
    Dec 2006
    Location
    Vancouver, B.C.
    Posts
    1,353
    Post Likes
    Your black prob is your reference probe when checking DC electricity. When you place your black probe on a point, then use your red probe to test another point, you are determining if that red probe is at a higher or lower potential (voltage) than the black probe. The readout on your display will indicate a voltage that may display a negative symbol in front of it depending on the result. That result indicates the difference in potential between those two points as measured by the red probes position. I suggest you play around with a 9V battery and see how your leads mesure voltage and where they are placed when you mesure a positive vs a negative voltage. 9 V batteries have their polarity clearly marked so its a quick and easy experiment.

    With AC... well the polarity is alternating (AC = Alternating Current) so your polarity is constantly changing (Hz)

    Never try to check resistance on a live circuit. This is where a quality meter may really save you one day. Specially when learning. Have a look at the Fluke 116. Its a solid candidate as a great beginner meter and will serve many very well through their whole HVAC career.

    Depending on your meter, you can sometimes mesure a limited current through your leads (usually 10A Max but changes based on your meters specs and the meter leads you are using... cheep leads... dont even get me started on those) but you wont get a proper reading if you are trying to mesure in parallel.

    Knowing this doesnt make using a meter safe. Knowing this doesnt mean you can troubleshoot anything better or anything at all. This is a drop in the ocean when it comes to the basics of electrical troubleshooting. The interweb has some great beginner electrical kits that you can build and learn electricity on. Battery operated stuff. Not lithium battery (that can pack a punch) but common alkaline type stuff. Safe to learn the basics and gives you something fun to experiment with. Always be careful with things that store energy. Batteries in particular because the amperage they can produce will fry your mind, but capacitors are particularly dangerous because they can hide in circuits and at times keep them live even after you power the unit off.

    Have fun, the electrical troubleshooting is an addicting puzzle. Just be careful because it will literally jump out at you if you get too close to it, and it doesnt offer many second chances when you get it wrong.
    Quickly, I must hurry, for there go my people and I am their leader!

  4. #24
    Join Date
    Mar 2015
    Location
    Medford, N.Y.
    Posts
    7,740
    Post Likes
    Quote Originally Posted by RandallJ. View Post
    I don't know how to use a multimeter. I know reds for hot and blacks for common but for voltage does that mean the red probe goes where the voltage would come in and black where it goes out?
    I like the "I KNOW" part. Yeah right! LOL.

    You would not touch anything electric, w/ me, until AFTER you explain to me what electricity is. I don't like fried,injured,DEAD, Apprentices. I highly recommend you changing your thinking about your and my safety. You will BE GONE if I catch you lying to me about safety. Not "knowing" is one thing, "knowing" and not "doing" is a whole other subject.

  5. #25
    Join Date
    Oct 2011
    Location
    Culver, Oregon (Central OR)
    Posts
    3,912
    Post Likes
    Don't ever put your hand on a piece of equipment until you have verified, your journeyman has verified, that it isn't live. Could save your life.
    "Life, Liberty, and Levin!"

  6. #26
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    29,820
    Post Likes
    Problem is, the first thing you do when you walk up to a unit is: Do not turn the power off.


    Quote Originally Posted by Adlerberts-Protege View Post
    Don't ever put your hand on a piece of equipment until you have verified, your journeyman has verified, that it isn't live. Could save your life.
    I do a triple evac with nitro to remove non condensables.

  7. #27
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    29,820
    Post Likes
    To the OP:

    Safety first. When it comes to electricity, try not to ever touch the unit. Meaning, do not lean on the unit. Do not put your hand on the unit to brace yourself. These are all too easy things to do and can easily lead to an electrocution.
    I do a triple evac with nitro to remove non condensables.

  8. #28
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    12,388
    Post Likes
    OP, have you gotten a job in the trade yet?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  9. #29
    Join Date
    Dec 2020
    Posts
    45
    Post Likes
    Thread Starter
    @thatguy thank you that was helpful. I'll take a look at that fluke. What I wanted to do depending on what happened with work was do continuing education for reading diagrams and HVAC specific electrical.

    @rider77 No not yet. I graduated 1/29. Getting things lined up to get my EPA and drivers licence and then get ahold of a guy in town that handles the HVAC side of the local union. I do have some shops lined up that take green apprentices. So I'm just getting things ready at the moment .

  10. #30
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    12,388
    Post Likes
    Excellent. If you get into the locals apprenticeship program, you’ll have 5 years of work and night school to teach the fundamentals.
    Electrical is a big part of that. I teach several electrical classes in my hall.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  11. #31
    Join Date
    Dec 2020
    Posts
    45
    Post Likes
    Thread Starter
    Yeah from the school work I did It was pretty clear that Im gonna need a better grasp of the electrical. My next goal is to be able to read diagrams better.

    I didn't realize that there would be more school with the union gig. That's great though. Before I started school I had accepted the fact that it's going to be a lifetime of learning and buying tools and all of that.

  12. #32
    Join Date
    Sep 2015
    Location
    Ontari-ari-ari-o
    Posts
    2,316
    Post Likes
    Quote Originally Posted by RandallJ. View Post
    Yeah from the school work I did It was pretty clear that Im gonna need a better grasp of the electrical. My next goal is to be able to read diagrams better.
    It all comes with time.

  13. Likes crazzycajun liked this post.
  14. #33
    Join Date
    Apr 2020
    Location
    Garner NC
    Posts
    3,200
    Post Likes
    Think of a multi meter as an audio/visual reader of electrical! Volts/Amps/Ohms A light switch is a reader of the visual kind.

  15. #34
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    12,388
    Post Likes
    Quote Originally Posted by RandallJ. View Post
    Yeah from the school work I did It was pretty clear that Im gonna need a better grasp of the electrical. My next goal is to be able to read diagrams better.

    I didn't realize that there would be more school with the union gig. That's great though. Before I started school I had accepted the fact that it's going to be a lifetime of learning and buying tools and all of that.
    Absolutely, a good tech realizes they will never know it all.
    Most of your issues will be electrical based. A lot of apprentices think it’s all about gauges and refrigerant, but your meter will be your most used tool besides a multi screwdriver.
    What area/local are you in?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  16. #35
    Join Date
    Dec 2020
    Posts
    45
    Post Likes
    Thread Starter
    Local 404, Lubbock Tx.

  17. #36
    Join Date
    Mar 2008
    Location
    kansas
    Posts
    1,995
    Post Likes
    https://www.fluke.com/en-us/learn/bl...-safety-videos
    Not exactly what your looking for, but something for consideration
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •