RV outlet

Discussion in 'Electrical Forum discussion & Blog' started by rrcur, Jun 20, 2012.

  1. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA


    1) Go back to what JW was writing about circuit sizes in the discussion of stolen wire from last week for why it is better to work to the smallest ampacity as possible.

    2) There will be essentially zero voltage drop issues unless the AC is 100' from the panel. He said it was only a few feet away. Not an issue. If it was, one could still install 12ga but use a 15 amp breaker.

    3) The OP posted that the label on the unit indicated something like 11.2amp max. I suppose the head pressure could take the demand past 15 amp long enough to trip the breaker. I'd defer to an AC specialist on that, but I am inclined to think that it would not.
    Last edited: Jun 23, 2012
  2. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    No need to get any of your garments in a twist.

    We agree. The OP is well advised to get a pro in to set him up if he is at all hesitant.

    The OP keeps banging on about having some 10-3 that he does not need, yet he seems desperate to get value out of it.

    And it does not go to the window that he wants to set the AC in.

    I'd be astonished if a pro would go to the trouble to pull back some 10-3 and then re-purpose it. Why do so? Apparently the OP needs about 10' of 14ga. Good lord. What does that cost if you get the hardware store to spool it off the spool? I could get the job done quicker and cleaner my way, and that is certainly how I would insist the customer let me do it, and how I would advise my neighbor or friend do it, were he/she to ask.
  3. rrcur

    rrcur New Member

    Messages:
    14
    Location:
    Southern Maine
    Ok. Thanks again to all of you for the comments.

    For the record, the panel board appears to be fairly new. It's a Murray Catalogue # LC130DC: Model 19 Type 1 enclosure, Type F panelboard with a 100 amp main breaker (service disconnect) inside the panel at the top. It appears to have 30 slots. Of these, 18 are currentyl in use. Of these 18, 14 are Romex-like sheathed cable, and 4 are the original metal-sheathed two-wire cable with the ground (such as it is) by way of the flexible metal jacket. There are no sub-panels, other than a disconnect switch in the detached garage. The garage is fed from the main house panel by buried cable.

    It appears to me that the previous owner upgraded the wiring to the kitchen and the bathroom to GFCI circuits and Romex-type wiring when they "re-modeled" several years ago and left the old wiring in the rest of the house. There are a few locations visible in the basement where a sheathed metal cable was extended with Romex, which I don't like very much.

    The outlets, other than kitchen and bathroom, are for two-pronged plugs (no ground hole), but the outlet boxes read as grounded at all but two of these outlets. I've been cautioned not to assume this is a machine ground and to be cautious about plugging heavy equipment or large appliances into these.

    If I can find some free time, and if I'm feeling brave, I'll probably buy a non-contact voltage detector, shut off the service disconnect and replace the 30 amp breaker mentioedn above with a 15 or 20 amp version.

    If this goes well, maybe I'll consider adding a couple more circuits and replacing the accessible sheathed cable in the basement. Second floor and first floor ceiling stuff, I think I leave to someone with more experience.

    I'm all good to go on fishing wire and installing the new box under the window for the a/c. I just need to get my act together on the breaker.
  4. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    A Murray panel is excellent news: absolutely the most common, solid and readily available panel and breakers. Cheap too. And you have plenty of room, there is no issue of it being a sub panel which can trip up the newbie.

    A master disconnect. Seriously. Once you flip that off, you really need to be attempting suicide to end up deceased. This is as modern and as reliable a bit of hardware as you are going to find. Once you flip that to the off position, the buss bars that the breakers hang on will be de-energized. The non-contact tester is an excellent idea.

    You can certainly consider fitting three prong outlets where you find a ground. Spend a few dollars: buy the better equipment. Receptacles can be bought all day long for 17 cents each. And they are utter junk. If the receptacles you are considering are costing you $1.50 or so, you are likely buying solid stuff. A clue is the yolk. That is the metal strap at which it is screwed to the box. If it passes all the way behind the receptacle, rather than passing into it at about half its depth, it is likely a good unit.

    Even better, but likely part of this sort of receptacle, is it having a bronze spring on one of the screws that ties it to the box. The code used to permit a receptacle to be considered grounded if it just had two screws going thru the yolk (into a metal box). Now it either must have the spring I describe (it is a flat thing) or a wire from the grounding screw to a legitimate ground in the box.

    Another aspect of the better receptacles that I like a lot: one does not wrap the wire around the screw. There is a flat plate behind which the bare wire, straight, is inserted, and then the screw torques down on that. I absolutely prefer these and have no problem getting clients to pay the slight (as a fraction of the entire project) cost of the upgrade. Just hold the two in your hands and you will see my point.

    If you are going to replace receptacles at all, learn what a multi wire circuit is. They present hazards if not understood, but are easy to understand, if you understand me. Ask and I will tell you more. The point comes down to being careful how you work the neutral, if you have multi-wire circuits in the house.

    Anywhere you do not have a ground, you can install a GFI to be assured there is no problem.

    Why are you adding circuits? Do you feel an actual need for them? Are you intending to make more use of the basement, such as having a wood working shop down there?

    If none of your breakers are tripping in the use that you are putting them to, you probably don't need more circuits.

    Having a few more outlets is a different question.
    Last edited: Jun 24, 2012
  5. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,301
    Location:
    Houston, TX
    Non-contact testers are a joke and are not a safe way to check if a wire is live.

    Many non-contact testers require current to be flowing before it can detect anything.

    If you are afraid to use a normal voltmeter, or do not have and do not know how to use one then it is best to call a professional.

    A non-contact tester will tell you if a wire has current going thru it, but is not a good tester for checking live deadened wires.
  6. Chad Schloss

    Chad Schloss Member

    Messages:
    330
    Location:
    USA
    hmm, my klein non contact dectector works finding dead end live wires. used it two days ago for just such a purpose, with two different circuits. I did have some issues with the $3 one I had from harbor freight though. if any doubt, definately test with a meter.
  7. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    That is absolutely not my experience with my Klien. It has never failed to give me a correct reading, although I do follow the instructions and check it on a known to be live circuit before I trust it to tell me that a circuit is cold.

    If you know the brand names of any non-contacts testers that behave as you indicate, please feel free to share. I will make a point of not buying one,
  8. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,301
    Location:
    Houston, TX
    The kind you can buy at wal+mart and the $3 ones from harbor freight, where many DIYers go to buy cheap tools.

    I agree some do work fair, but many people buy something cheap that may or may not work for 1 time use.

    I just do not trust them, and I will use a shorting wire, just to make sure the line is dead. The shorting wire also works if the line becomes energized for some unknown reason while you are working on it.

    A non-contact tester sure beats the tongue test, but a real meter or a neon bulb may be safer.
  9. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    I think your point should have been to only buy a quality tester. They cannot be had for less than $15 and still be quality. Klein and Greenlee are perfectly reliable.

    Often enough I start with the non-contact and then wade in with the multimeter, just to ensure that things are cold. But I feel much better if the non-contact has remained silent before I dig in.
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,126
    Location:
    New England
    My mother's house has BX(?) run to all of the original boxes, and over the years, in the plaster walls, the metal casing has corroded enough so the ground is essentially useless. To get 3-wire (ground contact) receptacles, the safest approved (least expensive) method is to substitute either the breaker for a GFCI or to find the first box on the run and install a GFCI receptacle there, then daisy-chain the rest on the circuit with the load side from the GFCI. For less tech savy people, if it ever trips, this can throw them a big curve since the CB is likely not tripped, but none of the outlets work! But, the better thing to do is to replace the wiring with a true power+ground cable. Some things, like surge suppressors, need the ground connection to provide full protection. And, the true, mechanical wire will allow the CB to trip should there be an internal device error if the chassis ever got energized.

    Since many newer appliances all come with a 3-prong plug, this is becoming more of an issue for older homes with 2-prong receptacles.
  11. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    One thing that is kind of a drag is that GFI's can get confused. If you put in a gfi breaker and all the wire flowing out of it and all the receptacles and switches and what have you are all in good shape, then the breaker could perform. But if that were the case, then you probably did not need the GFI breaker either.

    Same for putting a GFI receptacle in the first of ten receptacles: the chances that something anomalous at the fifth receptacle will trip up the breaker is real.

    I try to not have more than two receptacles down stream from a GFI. In most kitchens this works fine, two circuits, two GFIs, six places to plug in counter appliances. It takes a big kitchen to need more, and then, I'd just get the customer to pay for a third circuit.
  12. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    I will not trust any type of voltage tester that I can rub in my hand and make it go off.

    As the owner of my company the quickest way to be unemployed is to let me see one anywhere on the job and out the door that entire crew goes.

    Any meter I use must be marked category III
  13. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    OK.

    And so we are talking about Klien and Greenlee, and rejecting the crap from discounters.

    I agree that that is not obvious. But let's just spell it out for the Harry Home Owners.

    http://www.ni.com/white-paper/5019/en
    Last edited: Jun 24, 2012
  14. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Now research something that counts such as NFPA 70E or OSHA
  15. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
  16. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
  17. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    My point being that just because you have a meter is not all the knowledge needed to use it.

    The amount of surge voltages for a dwelling 15 amp circuit will depend on the size and length of conductors from the secondary side of the supplying transformer and the point on the system being tested.

    To blindly say that any meter could be used at any point of an electrical system has flaws.

    A category III is the smallest meter anyone should ever purchase to test voltages in their home. There are many reasons why a high voltage surge can occur on an electrical system and unless the meter is designed to handle the surge then accidents happen.

    The only non-contact meter that should be used is a clamp-on ammeter. Simply rub that meter that you have in the palm of your hand to see if there is a voltage present.

    I personally know of a case where the lead man held one to the brass screw on a receptacle while his helper turned off the breaker for receptacle replacement for a dishwasher. The mechanic only has one hand because the meter said the circuit was off but something somewhere went wrong. When current started flowing through him he pulled the device into the waste pipe for the sink causing an arc. A little over a week later they removed his arm to the elbow due to tissue damage from the current flowing through that portion of his arm and the burns he received.

    I highly recommend that non-contact voltage meters not be used for any reason along with any type of light emitting tester. If category III is not visible on the meter then don’t use it for testing circuits in our homes.

    In the event of a high voltage surge it is possible for an arc to surge through of any type of bulb and continue for a long enough amount of time to cause severe damage to any person. What are the probabilities of this happening, I don’t know but I do know if there is even the slightest probability then I don’t want to be the one doing the testing to see. I have already seen the results and know that there is a probability that it could happen.
  18. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    "I personally know of a case where the lead man held one to the brass screw on a receptacle while his helper turned off the breaker for receptacle replacement for a dishwasher. The mechanic only has one hand because the meter said the circuit was off but something somewhere went wrong. When current started flowing through him he pulled the device into the waste pipe for the sink causing an arc."

    I don't understand. How would having another meter have prevented some odd arc from getting around the breaker and down this poor guy's arm, and while we are chatting, how in the world did this guy get to grabbing the brass terminal of a receptacle that is tied to a hot, regardless of the position of the breaker or any indication from any meter, Cat III or not? The voltage was not there and then it was.

    Sheese. I swapped out a GFI live just the other day. The house is huge and has countless panels. I was not going to go chasing down the breaker. I was going to use good insulated tools and be careful.

    What you seem to be arguing is to pull the meter out before doing any work in the house. Not that I have never done that when I was working in a panel. Especially the Zinsco crap that is so common around here.
  19. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    The non-contact meter that he was using told him a lie. The breaker that the helper turned off was not the right breaker but when the Non-contact quite ticking he thought it was off.

    The voltage was always there but the little liar meter said it was off. One good reason why not to have one, they are liars. A good meter would have indicated that the circuit was still live but one of those trash can fillers just are no good. Did you try rubbing it in the palm of your hand?

    I will always chase down the breaker but I suppose this is because I have a full understanding that 120 volts on a 15 amp or larger circuit is more than enough to kill.
    It might be due to all the safety training I dish out each day and the math we do showing just how much heat energy that is available in a 120 volt 15 amp circuit. I think that the investigations that I have been involved with either directly or indirectly where someone was badly hurt working with something as simple as a 120 volt circuit might play a role in me making full sure that the voltage is off before working on anything.

    I guess that you must be getting the idea. Never and I repeat Never work anything live no matter the brand name of the panel. Pull out a good category III meter that gives me the amount of voltage on the conductor before touching anything. If it is service equipment that I am working in the meter must be a category IV.
    Let’s see what we have, 120 volts times 15 amps equals 1800 watts of continuous heat and using the rule of thumb of six times the rating of the device for 120 cycles this could be 10800 watts for two full seconds or just over 3100 BTUs more heat than is needed to damage the human body. Anyone that has ever used a cutting tool and cut through a live circuit can see by the damage done to the tool just how much heat went through that tool. Wonder what that kind of heat would do to one’s arm should it flow through the skin, muscle and blood?

    I would never trust any non-contact meter to assure me that the power is off. I would never connect any meter with less than a category III rating to the wiring system of any dwelling unit.
    The one thing that I know for sure and certain; no one has more control over my safety than me.
  20. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Well, I take you point now. You did not make your narrative very clear.

    I have never had an NC fail to tell me that juice was there, but I agree that using the full function meter before pulling anything out is an excellent idea.

    People are oddly afraid of sticking probes into sockets, but that certainly beats doing it with one's finger.

    I don't deny that 15 amps is about 150 times the energy needed to kick your ass, under the correct circumstances.

    But I'm not giving up my NC tester.
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