Buyers of Modules and Camps built in Canada and imported to
Alaska suffer consequences of deficiencies in the Canadian Electrical Code
by Gerald Newton
The Canadian Electrical Code is not equal to the National Electrical Code.
This does not mean that the Canadian Code is inferior; in fact, the Canadian
Electrical Code has many requirements not found in the NEC: for instance,
requirements for Cathodic Protection, Automobile Heater receptacles and
clearances for cable trays. However, some requirements found in the NEC and
rigidly enforced in Alaska are simply missing from the 1993 CEC. Therefore, if
you are buying or working on modules or camps built in Canada-here are some
things to look for.
The standard requirement for work clearance for a 208/120 volt or 240/120
volt panelboard is three feet in front, 30 inches wide, and 6 ft 6 inches high.
This work clearance is measured from the front of the panelboard and the
clearance must go to the floor. Additional clearance requirements for other
voltages and conditions can be found in tables located in Article 110 of the
NEC. These clearance requirements are also enforced in Alaska for switchboards
and Motor Control Centers. But the Canadians have differences here. Their Code
says "A minimum working space of 1 m (about 39 inches) with secure footing
shall be provided and maintained about electrical equipment such as
switchboards, panelboards, control panels, and motor control centres which are
enclosed in metal, except that working space is not required behind such
equipment where there are no renewable parts such as fuses or switches on the
back and where all connections are accessible from the locations other than the
When a provincial inspector was questioned in Edmonton Alberta, he explained
that this requirement of one meter about equipment is measured from the busbars
not the front of the equipment, and the clearances are not required to go to the
floor. Again and again, Canadian built modules are found to not meet the NEC
work space requirements because of this difference in interpretation.
Additionally, the Canadian Code does not have Tables for varying conditions. For
instance if two 480 volt pieces of switchgear are facing each other, four feet
of clearance is required between them by the NEC; the Canadian Electrical Code
would only require one meter.
Dedicated Space above panelboards and Switchboards
Section 384-4 of the NEC is critical when installing panelboards and
switchgear. This section, often called the footprint rule, requires a dedicated
space the width and depth of panelboards and switchboards to extend from the
equipment to the structural ceiling, which does not include a suspended
ceiling. Likewise, this space must extend to the floor beneath the equipment.
The Canadian Code HAS NO SUCH REQUIREMENT. This costly deletion from the CEC has
cost thousands of dollars when Canadian built modules are modified to comply
with NEC section 384 4. There can be no piping, ducts, or architectural
appurtenances in the dedicated space with few minor exceptions.
Overcurrent protection for Lighting and Appliance Panelboards
The NEC defines lighting and appliance panelboard as one having more than
ten percent of its overcurrent devices rated 30 amperes or less, for which
neutral connections are provided. Most panelboards are lighting and appliance
panelboards. The NEC requires that these panelboards have overcurrent protection
either at the panelboard or on the feeder supplying the panelboard with one
exception for existing residential occupancies. There cannot be a transformer
between the panelboard and this protection by the NEC. But the CEC allows the
protection for this type of panelboard to be on the primary of a transformer
that supplies the panelboard. This difference between the NEC and the CEC has
cost tens of thousands of dollars on one job alone.
Other miscellaneous requirements
The derating requirements for over three current-carrying conductors in a
raceway are also different in the Canadian Electrical Code.
The NEC limits the number of overcurrent devices in a lighting and
appliance panelboard to forty-two by Section 384-15 There is no similar
requirement in the Canadian Electrical Code. Lighting and appliance panelboards
have been found in Canadian built camps with sixty-six overcurrent devices.
Table 2 of the CEC is the main ampacity table for not more than three
copper conductors in a raceway or cable. It is the Canadian equivalent to Table
310-16 in the NEC. There is one important difference in these tables. Table 2 of
the CEC allows the use of 110, 125, and 200 degrees centigrade conductors where
these higher temperature ratings are acceptable to the "inspection
department." Canadian built camps have been found with conductors with 125
degree centigrade insulation used at the 125 degree centigrade ampacity
terminated on equipment rated at only 75 degree centigrade. An investigation
revealed that the Canadian inspectors had not inspected the camp and that no
permission had been given to use the higher temperature conductors. In
fact, when a provincial inspector was asked why the modules built for export are
not inspected, he replied, "Because you Americans wouldn't accept our
inspection anyway. We wouldn't accept yours either."