Preferred Grounding Configuration, 208 Vac Input And Output, Non-Isolated Load; Figure 4. Preferred Grounding Configuration, 208 Vac Input And Output - Liebert Series 600T Installation Manual

GROUNDING
ELECTRODE
PER NEC 250-24

Figure 4. Preferred Grounding Configuration, 208 VAC input and output

7.4. Preferred Grounding Configuration,
208 VAC Input and Output, Non-
Isolated Load, Wye-Connected
Service
A few applications in this power range have 208
VAC input and output, and a connected load
consisting of multiple Power Distribution Units
(PDUs), panelboards, switchboards or other items
of load equipment which do not have isolation
transformers.
Notice in Figure 4 above that the UPS module
main input and bypass input are connected to a
grounded-wye service. In this configuration, the
UPS module is not considered a separately derived
source.
Liebert Series 600T UPS, 65-225 kVA, Single Module
The UPS module output neutral and the load
neutral are solidly connected to the building
service neutral, which is bonded to the grounding
conductor at the service entrance equipment.
This arrangement is typical for systems with 208
VAC input and output. However, it does not
provide any isolation or common-mode noise
attenuation for sensitive loads.
11