ERICO ISODC Isolated Downconductor System - Manual (Page 4)

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Design requirements of the ERITECH ® Isolated Downconductor system is based on two sections of the IEC 62305-3 standard
“Protection Against Lightning – Part 3: Physical damage to structures and life hazard”. For correct installation the system must be
designed and installed in accordance with these requirements.
Step 1. Determine the required height of the air terminal to provide protection according to IEC 62305 Protection Angle
Method (PAM)
Step 2. Determine the length of Isolated Downconductor so separation distance (IEC 62305-3 section 6.3) does not
exceed 1000 mm
Step 3. Meet ERICO’s mounting and installation requirements and interconnect to a standard compliant grounding or lightning
protection system
IEC 62035 Protection Angle Method
An air terminal is assigned a protective angle where any equipment fully located within the protected volume is deemed to be
protected. The protection angle provides a cone volume of protection with the angle determined by the height of the air
terminal above the object and the Lightning Protection Level (LPL).
Determine the required minimum height of the air terminal tip above the top of mast/items to be protected. It is recommended
that highest LPL be used (i.e. LPL I). Alternatively the required Lightning Protection Level can be determined by IEC 62305-2
risk assessment.
80
70
60
50
40
30
20
10
0
0 10 20 30 40 50 60 2
I II III
IV
Class of
LPS
(LPL)
Height (m)
Pr
otection Angle
␣Њ
Figure 1. IEC 62305 Part 3, Table 2 details the protection angle.
1. DESIGN