Technical information

Particularly OSHA is more restrictive in the prescriptions for components

admitted for use in the electrical plants/equipment.

OSHA regulations only permit the use of components that have been tested and

certified by an NRTL test laboratory.

Meanwhile NEC foresees the use of components that are considered still suitable for use.

In fact this difference is annulled by the habit of AHJs to accept only certified

components, admitting non-listed components only in a few and justified cases.

In both texts there is a clear reference to the fact that components have to be

installed in full conformity with the use conditions foreseen in the certification.

In some specific sectors an important reference is the ”Electrical Standard for

Industrial Machinery” (NFPA 79). It is a standard that transfers the EN 60204-

1 to the American industrial world without altering the sections related to

machine operation (e.g. human-machine interface, control circuits, etc.) but

replacing the paragraphs related to electrical system layout with the similar

sections taken from NEC.

Industrial Machinery means:

a) metal working machines tools, inlcuding also metal cutting and moulding

machinery

b) plastic processing machinery, including thermoplastic and thermosetting

moulding, extrusion, blowing, specialised jobs and size reduction

c) woodwork machines, including of woodwork machines, laminators and

panel saws

d) assembly machinery

e) material handling machinery, including industrial robots and transfers

f) trial and testing machines, including measuring machinery using co-

ordinates and “in-process” measuring devices

Specific installation standards can be added to the federal rules such as those for

machine tool equipments, UL508A “Industrial Control Panel”.

UL508A is divided into a section containing rules applicable to all equipments to

which other sections are added, that include rules for some specific machinery

types (Industrial Machinery, which includes design parameters defined in NFPA79,

as well as lifts, conditioners, sea environment and others).

In Canada:

Every state issues its own safety at labour rules (for interstate workers and other

specific sectors, it is the “Canada's occupational safety and health” - CANOSH) and

the CCOHS plays the role of guiding and co-ordination body.

For the electric safety,the local installation code is always taken as reference,

which derives from the Canadian Electrical CODE (CEC) published by CSA.

Therefore, the CEC is the main reference to design the equipment.

INTRODUCTION TO NORTH AMERICAN STANDARDS