Grounding to existing circuit

[dkerr]

Old House, I believe was built in 3 stages with many years apart. The older sections of the house has ungrounded outlets, but it has one newer section at the back that has some grounded wiring.

The question is can the ungrounded outlets in the older section be undated to grounded outlets by running and grounding to existing grounded outlets at another location ?

This is a friends house and have already updated all outlets on the first floor to new grounded outlets (grounding down to the basement water pipe at the city's entrance location) water pipe grounding is allowed in Canada.

But the upstairs is not yet updated. Is it allowed to ground a different circuit to another circuits ground ??? It just saves running / routing grounds wires to the basement but will do that if necessary. Is there a limit as far as ground wire runs as far as how many outlets or ciruits a single ground wire can serve ?? (in Canada)

I personally would prefer having a separate ground run, but just asking if the other is available if easilier

[joed]

Copied this deirect from the ESA site.
http://www.esasafe.com/consumer/esafaqs.htm

The Code states "Where grounding type receptacles are used in existing installations to replace the ungrounded type, the grounding terminal shall be effectively bonded to ground." The Code permits bonding the receptacle by connection to a metal raceway or cable sheath that is bonded to ground; or by connection to the system ground by means of a separate bonding conductor; or by bonding to an adjacent grounded metal cold water pipe.

As an alternative to bonding the Code also states "grounding type receptacles without a bonding conductor shall be permitted to be installed provided each receptacle is protected by a ground fault circuit interrupter of the Class A type that is an integral part of this receptacle; or supplied from a receptacle containing a ground fault circuit interrupter of the Class A type; or supplied from a circuit protected by a ground fault circuit interrupter of the Class A type. Where this option is used, no bonding conductor is permitted between outlets unless that bond conductor is in turn connected to ground.

GFCI protection of the receptacles protects against possible shock hazards but does not provide a ground reference to the U-ground slot of the receptacles. Some appliances require a bond be connected to the U-ground slot in order to function properly. For example, surge protective devices for computer equipment will not function without a ground reference.

Ontario Electrical Safety Code Rule 26-700.