will mac pros run off older 110 volt wiring in my home?

Discussion in 'Mac Pro' started by Sossity, Mar 24, 2011.

  1. Sossity macrumors 65816

    May 12, 2010
    I know I have asked a similar question earlier on, but I did not know the exact voltage of my home then, I asked someone who knew my home's wiring, & they said it was 110 volt. The home was built in the 1950's, & I see these are powerful modern computers & I was a little concerned about the safety, as most of the outlets, & the ones in my room are 2 prong.

    would I be able to have a mac pro & run it safely in my home?
  2. Riot Nrrrd macrumors regular

    Riot Nrrrd

    Feb 23, 2011
    Lost Androideles
    I don't think the voltage is the problem (my home was built in 1948, for example) - it's the fact that you don't have 3-prong grounded outlets.

    You really should have an Electrician come out and evaluate your wiring, panel etc., IMHO. Better safe than sorry, right?
  3. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    There's no problem at all with the power supply. At most, even a desktop and display would take about the same as a few 100W light bulbs. A notebook even less than one.

    But, you are correct in that an ungrounded outlet is less safe - though I'm guessing you're already running TVs and other electronics off the 2-prong outlets with no problem (most don't have a 3-prong anyway).

    If your computer does have a grounded plug, there are a couple of options: There are 3-prong adapters which connect the ground to the plate mounting screw. The best would be to have an electrician convert the outlet and test the ground (or someone comfortable doing such work - it's not too involved).
  4. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    If you are in the USA each state has a code and each town may have more rules. I live in New Jersey and state law allows a homeowner to wire his own home as long as he or she is living in it. I re-wired my entire home in the 90's because it had aluminum wiring. I went to my township and got permits and had it all inspected once it was done.

    In the late 60's and early 70's due to a world wide copper shortage the USA allowed Aluminum wiring for private homes in many states including NJ. Thousands of home fires later it is now banned in all 50 states for private homes.

    My point is check your local laws it may be something you are allowed to DIY or you may need a licensed electrician. It is a good idea to at least do a few outlets in your home.
  5. Darien Red Sox macrumors regular

    Dec 13, 2010
    CT, USA
    Use a electrical tester and stick one prob in the hot and the other on the faceplate screw, if it works that means that you have a ground and installing a grounded outlet would be easy.
  6. nanofrog macrumors G4

    May 6, 2008
    I agree.

    Depending on the exact year of construction and location of the house (exact building code in effect at the time for the dwelling), there may or may not be a ground wire in the box. If it's missing, then it's more complicated than just replacing the outlet, as one needs to be run (hopefully, it's on an exterior wall, where a ground rod could be driven into the ground where the box is, hole drilled through the wall, and the ground wire run through the hole to the ground rod). An interior wall would present additional challenges (and cost).
  7. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    You can either replace the outlet (about $2) or buy an adaptor for maybe $8 that replaces the face plate.

    In the absolute worst case who can hire an electrician who can run a ground wire back to the service entrance panel. He would charge you a fraction of what a Mac Pro costs. You might need thisif the house were very old, say from the 1920's or before but even then I gues it would have been retofited already. A 50's vintage house could use the simply solutions above. Most hardware stores have what you need
  8. nanofrog macrumors G4

    May 6, 2008
    Only if there is a ground wire in the box.

    Individual ground wires to each box wasn't mandated by the National Electrical Code until the late '50's (they meet every 3 years, so working backwards, would put it in the 1957 code). Local codes could have required it earlier than that, and is where the physical location comes in.
  9. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    He could be lucky and the house used metal shielded wire instead of romex type.

    A lot of older homes use it.

    the metal shield is the ground if it is installed correctly . see the link to ebay. of course the ebay wire is new code and has a wire inside for the ground. in the 50's the code did not require the inside wire. personally I would call an electrician
    to play it safe If I were you.


    of course this may not be the case. then a direct ground to a grounding rod can work. like nanofrog mentions.
  10. nanofrog macrumors G4

    May 6, 2008
    Possible, but most I've seen from the '50's is Romex of that era (i.e. ceramic isolators and individual wires were already replaced if it's a really old house). But the pre ground wire stuff is only 2 conductor, no ground wire (paper and fabric of some sort, possibly even asbestos - not sure what the fabric yarns are made of at that time, as nylon did exist <1935 by Dupont>).

    In residential construction from the '50's?
  11. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    Well A lot of NYC and LI homes.

    The ones I did work on were in three different spots
    Ozone Park Queens,
    Floral Park Queens
    and New Hyde Park L.I.

    All used Steel clad two wire black and white to steel boxes. The boxes were ground via the steel clad case. Sometimes the steel clad would rust out and the ground would be lost. I never did enough homes from the 50's other then those three areas. One of the early posters mentioned put a meter on the hot wire and the screw of the faceplate to test. This is how we tested them to see if the ground had failed. Thats why my saying a lot of 50's homes was a bit incomplete it is based on two summers work in those three areas.
  12. nanofrog macrumors G4

    May 6, 2008
    This is odd to me (but I wasn't around in the 50's, nor have I ever lived in NY).

    Given what you've posted, I'm curious if they had to conform to Commercial codes or if it was part of the Residential code at the time (I'm used to conduit being used in commercially zoned structures, but wondering if it's a result of the proximity to the Atlantic Ocean). You've piqued my curiosity here.... :D

    What I've researched was the result of running into no grounds on the 120VAC single phase in my current home which was completed in 1956. So I had to do the ground rod method + GFCI's for the computers and other sensitive equipment. A previous home I had, was completed in 1959, and the metal boxes were grounded (easy to replace the outlets to 3 prong). Both only followed the NEC in effect at the time of construction, and used Romex of the period (no ground wire in the stuff from '56).

    Another thing I found up in the attic that I don't care for in the current house (makes me nervous as to load), is that they use 20A breakers, but when the 12AWG wire hits the room it's meant for, it then gets split off into multiple legs (3 per bedroom) of 14AWG (at least it's done in a junction box). I realize the 14AWG wire distance isn't that long, but I still can't help but think of the potential of running 20A continuously off of one of those runs. The fewer number of outlets for load distribution doesn't help either (makes me wonder about others with this that may have had a fire as a result, as they'd likely have no idea of any potential danger).
  13. Ca$hflow macrumors 6502


    Jan 7, 2010
    London, ON
    3 options are available.

    1) Hire an electrician to install ground. Not just a 3 prong socket as the ground on the socket would not be connected to anything. If there is a sudden ground then the breaker will trip or fuse downstairs would burn out. This can be expensive.

    2) Install a 3 prong socket yourself. Since the ground would not be connected to anything, then plug a surge protector in-between the computer and the socket. there is a reset on the power bar.

    3) Here in ontario if there is no ground then a GFI would suffice according to code. One can be picked up at the hardware store for $15. A GFI (Ground fault interrupter). It would trip if it senses a sudden ground of more then .005 amps. They have a reset button on them too. They are mandatory if 3 feet away from a water source.

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