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Thread: Load connected to two meters

  1. #1
    Join Date
    Oct 2018

    Load connected to two meters

    I live in Jordan. We have a 380Vp-p, star, 4-wire, earthed neutral connection to the building. We get 220V to the apartment. I have recently installed an EV charging station for my car. The electrician connected the station’s hot wire from one of the building service lines (one of the phases). But, for some reason, he could not return the neutral wire to the same meter. Instead, he connected it to my apartment’s neutral which is connected to a different meter.

    Is this configuration safe? or does it cause problems in billing?

  2. #2
    Join Date
    Feb 2003
    Seattle, WA
    I am allowing this thread, because the OP does not appear to be planning to do any work himself (i.e., this is not a DIY question - not yet anyway).

    I believe the circuit will function, so that you might not be able to discern that a safety problem exists. But a safety problem does exist. It will come into play when a future electrician does some work on one of the meters or a downstream load. They might think they have de-energized the circuit, but it might still be live. Much depends on exactly how the connections were made (i.e., to exactly what points on the system).

    Welcome to the forum.
    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

  3. #3
    Join Date
    Dec 2012
    Placerville, CA, USA
    From the point of view of metering, most if not all revenue meters do not measure the current in the neutral, so you are not likely to have billing related problems. The safety question, as charlie stated, will depend on a number of factors we do not know yet. The biggest single potential problem would be if a future electrician though that the neutral in the apartment panel was safe (not carrying current) just because the apartment disconnect was open. He would be at serious risk of getting a shock on a "disconnected" neutral based on the other service still being connected.
    At an absolute minimum there should be a tag on the neutral indicating that it is sourced from a different panel.

    The configuration would almost certainly be an NEC violation, if there is code enforcement at the site.

  4. #4
    Join Date
    May 2018
    Jamaica and london
    If the meters are the same types as used in US and Jamaica, the no problem in billing should occur, which was your second question, as the neutral is not used for the meter to operate.
    however, in the UK there could be a problem as UK meters require the neutral, being Smart and sampling both sides of the current used in a residence...
    if the electrician is feeding the charger, as you stated, from not your meter but another meter, then that meter is being charged for whatever use the charger is used for... your own meter sees no difference... that said, your neutral feed from the meter creates a fault problem in servicing the charger and if a vehicle charging fault occurs.

    i would work with the building owner and the owner of whatever meter the charger is connected to in order to get a better electrician to run the circuit properly.
    Student of electrical codes. Please Take others advice first.

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