Researching the requirements 23
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In a steel-framed building, the SL-1 ground interface must have a
connecting reference to the building steel on the same floor on which it
resides (or within one floor).
Note:
Northern Telecom does not recommend the use of building steel
as part of the SL-1 ground system.
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Proper wire sizing of the System Ground Reference conductor ensures
compliance with this requirement provided the building ground has been
properly installed as per NEC rules and regulations and the associated CEC
regulations.
Using an Isolated Ground bus is often a lower cost method but may not be
allowed by all telcos and may be prohibited by local ordinances.
Note:
All voice and data lines leaving or entering the SL-1 system
(which run external to the building) must have fault protectors that
connect directly to earth ground. Fault protectors provide E&lI/RFI
protection outside of the SL-1 system.
AC service panel
Dedicated versus shared power
Dedicated AC power transformers are preferred; however, a shared
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transformer or distribution is acceptable.
The following figures identify the differences between dedicated and shared
distribution and between isolated and non-isolated grounds:
Installation planning 553-3001-120