Technical information

1.2.3.1 Differences between a motor protector “Manual Motor

Controller” and a “Manual self-protected combination

motor controller Type “E” in the United States

)

The size of the product, for instance, is one of the most important elements of dif-

ferentiation between UL 489 and UL 508. Generally speaking, the devices accord-

ing to UL 489 have a physical size definitely bigger than the components of the

UL 508, in order to satisfy the isolation distance imposed by the norms and by the

NEC regarding the feed circuits or feeder.

Therefore, if the motor protector is used in North America as a protection device

“Type E”, it means that it must have the same distances at the connection side to

the line required according to UL 489, which have been changed and is included

also in the UL 508 edition of July the 16th, 2001 for this kind of products:

•1inch (25,4 mm) for an aerial distance

•2inches (50,8 mm) for a above-ground distance;

In general, these distances are higher than those built in the components with an

IEC standard. In fact, all the motor protectors which are manufactured according

to the European standard, turned out to be too “small” (apart from some

exceptions) to be compatible with the dimensions imposed by the UL 508

standards.Therefore, they lose their protection function against over-currents

(short-circuit).

A motor starter manufactured in Europe using an IEC rated manual motor starter

together with a contactor,in case of application in North America shall be

integrated with fuses or UL 489 automatic circuit breaker in order to provide

protection against short circuits.

) For Canada and particularly for the CSA, the certification of motor protectors has not been updated on the restrictions included in the UL 508

(e.g. new aerial distances and between the surfaces).

BRANCH CIRCUIT

Before

July the 16th,

2001 After

Aerial distance

”1”

Distance between

two surfaces

"2”

Above-ground

aerial