2 What is an fault arc - Die BG ETEM
2 What is an fault arc - Die BG ETEM
2 What is an fault arc - Die BG ETEM
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
8 R<strong>is</strong>k assessment <strong>an</strong>d calculation of <strong>arc</strong> r<strong>is</strong>ks<br />
Fig. 8.1: Overview on parameters <strong>an</strong>d procedure for r<strong>is</strong>k <strong>an</strong>alys<strong>is</strong> in connection with box-tested PPE<br />
The largest <strong>arc</strong> energy level determined for the case under study has to be compared<br />
with the protection level Wprot (equivalent <strong>arc</strong> energy). The equivalent <strong>arc</strong> energy<br />
<strong>is</strong> that one where the protective effect of the PPE <strong>is</strong> still given for the according<br />
exposure d<strong>is</strong>t<strong>an</strong>ce a (see Tab. 8.1).<br />
Class Protection degree Test level W<strong>arc</strong>P Protection level Wprot<br />
1 Basic protection 158 kJ<br />
2 Increased protection 318 kJ<br />
Tab. 8.1: Protection levels of PPE tested according to the box test<br />
(1… 2,4) . a ( 300 mm)<br />
(1… 2,4) . ( a )<br />
The PPE test level W<strong>arc</strong>P = WLBP <strong>is</strong> valid for the heat tr<strong>an</strong>sm<strong>is</strong>sion conditions <strong>an</strong>d the<br />
exposure d<strong>is</strong>t<strong>an</strong>ce of a = 300 mm of the box test set-up. Following the equivalent <strong>arc</strong><br />
energy has to determined by<br />
Wprot = kT . a<br />
( )<br />
300 mm<br />
Working place<br />
Protective devices Electric System Power equipment<br />
tk UrN Sk" d a kT<br />
Normalized <strong>arc</strong> power kp<br />
Electric <strong>arc</strong> energy expected<br />
W<strong>arc</strong> = WLB<br />
2<br />
. W .<br />
<strong>arc</strong>P<br />
300 mm<br />
W<strong>arc</strong>P = WLBP<br />
W<strong>arc</strong>P <strong>is</strong> the test level <strong>arc</strong> energy according to Table 5.2. The factor kT takes into account<br />
the electric power installation, particularly the volume of the opened compartment<br />
where the <strong>arc</strong> <strong>is</strong> expected to burn. As a st<strong>an</strong>dard <strong>an</strong>d particularly for narrow<br />
constructions with side <strong>an</strong>d back walls <strong>an</strong>d low volume (house service boxes, d<strong>is</strong>tribution<br />
boards etc.) th<strong>is</strong> factor <strong>is</strong> kT = 1, for wider burning r<strong>an</strong>ges (e.g. mainly back<br />
PPE<br />
PPE test level<br />
Arc flash protection class<br />
Equivalent <strong>arc</strong> energy (protection level)<br />
Wprot<br />
2<br />
2<br />
. 158 kJ<br />
. 318 kJ<br />
35
Change language