On the exterior is can be as far as you want basically...once you enter the building this is what you get...
(1) Consumer’s service equipment location
Rule 6-206 requires that the service box or other consumer’s service equipment shall be as close as practicable to the point where the consumer’s service conductors enter the building.
Where judgment is required about “as close as practicable", the following may be used for guidance on the maximum length of run:
(a) 1.5 m into rooms or areas of combustible construction; or
(b) 7.5 m into other areas provided: the wiring method is rigid conduit, electrical metallic tubing (EMT) or a cable with a continuous metal sheath or interlocking armour and the conduit or cable is mechanically protected where it is within 2 m of the floor.
That is the Ontario perspective.
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