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Costly Deficiencies Found in Canadian Electrical Code


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.

Work Clearances

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 back."

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."

© 1996 Gerald Newton. All rights reserved.