Isolating Distances And Insulating Equipment - Siemens SENTRON 3WL10 Equipment Manual

For the withdrawable breaker, two alternatives are possible to achieve continuity and
equipotentiality of the grounding between the circuit breaker and the protection circuit of
the switchboard:
• Connection of the guide frame to the protection circuit with a cable in accordance with
IEC 61439‑1, Section 10.5.2
• If a conductive connection between the guide frame and the grounding of the switchboard
is ensured via the metal base (floor mounting) or the metal wall (wall mounting) of the
switchboard panel, no additional grounding is required. This means there must be no
insulation material between the circuit breaker and the grounded metal of the switchboard
panel.
4.2.2

Isolating distances and insulating equipment

When live parts are installed, the following rules must be followed:
• Minimum isolating distance between the phases:
• Isolating distances within the switchboard panel
To observe the isolating distances inside the panel, the following minimum dimensions for
the interior of the panel must be observed:
Insulating measures
Note
The insulating equipment is only required for the fixed-mounted version of the circuit breaker.
No insulating equipment is required in the withdrawable breaker.
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
Equipment Manual, 10/2023, L1V30499596002-03
Rated insulation voltage U
1000 V
4.2 Power supply, grounding, and connection
Smallest distance
i
acc. to IEC 61439: 14 mm
Siemens recommendation: 25 mm
A
3-pole
Fixed- 250 mm
mounted
breaker
Withdrawa‐ 280 mm
ble breaker
Application planning
B C
4-pole
322 mm ≤ 440 V: 332.5 mm
> 440 V: 382.5 mm
350 mm ≤ 440 V: 390 mm
> 440 V: 440 mm
D
130 mm
252 mm
147