In BC I see 400 amp services that are huge. 400 amp meter comes to huge 400 amp disconnect. Then there is a set of smaller branch disconnects each going to a load center. Does it have to be like this? Can I not just come off dual lugs on the meter's load side to two separate 200 amp disconnects and load centers?
Question: Can a 400 amp self contained meter base with twin lugs be used to supply two 200 amp combination panels in a single residential occupancy? Bulletin 6-3-3 gives an easement to using a dual lug meter base but only "where the subdivision of the service supplies separate occupancies or buildings".
Answer: Yes, 2002 Code Rule 6-200(2) does not require the services to be in separate occupancies or buildings. The service boxes shall be grouped where practicable in accordance with Rule 6-102(2); where it is not practicable a permanent diagram shall be posted at each service box indicating the location of all other service boxes in accordance with Rule 6-102(3). The Bulletin will be amended.
Rationale: Rule 6-102 permits only one supply service to a building (with exceptions). In the above installation there will only be one supply service that terminates at the meter mounting device.
Rule 6-104 permits up to four consumers services to terminate at any one supply service (Sect 0 defines a consumers service as that portion of the consumers installation from the service box up to and including the supply connection point)
Rule 6-200(2) permits more than one service box to be connected to a single consumers service provided the subdivisions are made in a multiple or dual lug meter mounting device and Rule 6-200(3) says for application of Rule 6-104 each subdivision shall be considered as a consumers service.
April 2002 Page 1 of 1 Bulletin 6-3-3
Dual Lugged and Multiple Meter Mounting Bases Rule 6-200 (page 28)
Meter mounting devices (meterbases) are available with dual lugs and questions have been asked about using them
as a splitter to supply two consumers services.
There has been inconsistent interpretation of the code in this matter.
The 2002 Ontario Electrical Safety Code Rule 6-200(2) permits more than one service box to be connected to a single
consumers service provided:
1. The subdivision is made in an approved dual lug meter mounting device rated at not more than 600 A and 150 V
to ground; and
2. The meter mounting device is located outdoors.
Where the service boxes are in the same occupancy, the service boxes shall be grouped where practicable in
accordance with Rule 6-102(2); where it is not practicable, a permanent diagram shall be posted at each service box
indicating the location of all other service boxes in accordance with Rule 6-102(3).
Self-contained 400 A rated meter mounting devices contain current transformers with automatic circuit closing
devices to short out the current transformer secondaries upon removal of the meter. Those concerned with
installation and maintenance on services with such meter mounting devices should be aware that removal of the
meter does not isolate the service.
Number of Subdivisions of a Service Where Multiple Meter Mounting Bases are Used
Multiple meter mounting bases used in residential installations require demand calculations to determine the
maximum number and ratings of sub-services. If no demand calculations are available the total of the ratings of the
switches fed from the multiple meter mounting bases shall not exceed the ampere rating of the meter base.
Multiple meter mounting bases may be accepted for non-residential installations. The combined ratings of the
switches/breakers supplied from the meter base shall not exceed the rating of the meter base.
In addition for all installations, the number of conductors per lug shall not exceed the number for which the lug is
Electrical Safety Authority