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Requirements pertaining to the necessary distances as appropriate for use of the terminal blocks in the area DIN EN 60079-11
(VDE 0170-7) “Explosive atmosphere – Part 11: Device protection by intrinsically safe features “i” (IEC 60079-11)” are defined
under Section 6.2 “Connecting point for external circuits,” Section 6.2.1 “Terminal blocks”. In general, the following can be stated
for terminal blocks based on figure 1: “Example of isolation of intrinsically safe terminal blocks with partition” in conjunction with
figure 2: “Example of isolation of conductive parts,” considering Table 5 – “Clearances and creepage distances and isolation dis-
tances.”

Outside
a) Isolated intrinsically safe circuits at least 6 mm
All PCB terminal blocks listed on the ordering pages as suitable for Ex “i” applications fulfill these requirements.
b) Intrinsically safe circuits and normal circuits (non-intrinsically safe) ≥ 50 mm.

Inside
a) Ex “i” to Ex “i”
b) Ex “i” to normal circuits
c) Ex “i” to ground
Based on Figure 2 and Table 5 in accordance with the selected protection level and the special requirements for separation dis-
tances as described in Sections 6.3.1 to 6.3.13, or in accordance with the alternative procedure for dimensioning of separation
distances given in Annex F.
Terminal blocks with smaller pin spacing may also be used for internal connections, provided they meet the require-
ments laid out in Table 5. (see below) (see below)

The exact clearances and creepage distances as well as separation distances based on Table 5 must be derived from the applica-
tion items cited above.

Legend:
1 conductive cover
T Distances based on Table 5
d Distance at outer connecting parts of
the terminal blocks according to 6.2.1

Note:
The dimensions indicated here represent the clearanc-
es and creepage distances around the insulation and
not the thickness of the insulation!

Dimensions in mm
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Figure 1a: Requirements for clearances and creepage distances for terminal blocks with isolated, intrinsically safe
circuits