Ngokuphathelene namazinga okushisa okusebenza kwesikhathi eside avumelekile kuma-cable cores, ukufakelwa kwerabha kuvame ukulinganiselwa ku-65°C, ukufakelwa kwe-polyvinyl chloride (PVC) ku-70°C, kanye nokufakelwa kwe-cross-linked polyethylene (XLPE) ku-90°C. Kuma-short-circuits (anobude obungadluli imizuzwana emi-5), izinga lokushisa eliphakeme kakhulu elivumelekile lomqhubi lingu-160°C lokufakelwa kwe-PVC kanye no-250°C lokufakelwa kwe-XLPE.
I. Umehluko phakathi kwamakhebula e-XLPE namakhebula e-PVC
1. Izintambo ze-Low Voltage Cross-Linked (XLPE), kusukela ekuqaleni kwazo maphakathi nawo-1990, ziye zabona intuthuko esheshayo, manje seziyingxenye yemakethe kanye nezintambo ze-Polyvinyl Chloride (PVC). Uma kuqhathaniswa nezintambo ze-PVC, izintambo ze-XLPE zibonisa amandla aphezulu okuthwala ugesi, amandla okulayisha ngokweqile aqinile, kanye nesikhathi sokuphila isikhathi eside (isikhathi sokuphila sokushisa kwekhebula le-PVC ngokuvamile siyiminyaka engama-20 ngaphansi kwezimo ezinhle, kanti isikhathi sokuphila kwekhebula le-XLPE ngokuvamile siyiminyaka engama-40). Uma kushisa, i-PVC ikhipha umusi omnyama omningi kanye namagesi anobuthi, kanti ukushisa kwe-XLPE akukhiqizi amagesi anobuthi e-halogen. Ukuphakama kwezintambo ezixhumene kuqashelwa kakhulu ngemikhakha yokuklama kanye neyokusetshenziswa.
2. Izintambo ze-PVC ezivamile (ukufakwa komoya kanye negobolondo) zisha ngokushesha ngokushisa okusheshayo okuqhubekayo, okwandisa imililo. Zilahlekelwa amandla okunikezwa kwamandla kungakapheli imizuzu eyi-1 kuya kwemibili. Ukushiswa kwe-PVC kukhipha intuthu emnyama ejiyile, okuholela ebunzimeni bokuphefumula kanye nezinselele zokuphuma. Okubaluleke kakhulu, ukushiswa kwe-PVC kukhipha amagesi anobuthi futhi agqwalisayo njenge-hydrogen chloride (HCl) kanye nama-dioxin, okuyizimbangela eziyinhloko zokufa emililweni (okubangela u-80% wokufa okuhlobene nomlilo). Lawa magesi agqwala imishini kagesi, okuphazamisa kakhulu ukusebenza kokushisa futhi kuholele ezingozini zesibili okunzima ukuzinciphisa.
II. Izintambo Ezingashisi Amalangabi
1. Izintambo ezivimbela ilangabi kufanele zibonise izici ezivimbela ilangabi futhi zihlukaniswe ngamazinga amathathu avimbela ilangabi A, B, kanye no-C ngokusho kwe-IEC 60332-3-24 “Ukuhlolwa kwezintambo zikagesi ngaphansi kwezimo zomlilo.” Isigaba A sinikeza ukusebenza okuphezulu kakhulu okuvimbela ilangabi.
Ukuhlolwa kokushiswa okuqhathanisayo ezintanjeni ezivimbela umlilo kanye nezivimbela umlilo kwenziwe yi-US Standards and Technology Research Institute. Imiphumela elandelayo iqokomisa ukubaluleka kokusebenzisa izintambo ezivimbela umlilo:
a. Izintambo ezivimbela ilangabi zinikeza isikhathi sokuphuma esingaphezu kwezikhathi ezingu-15 uma kuqhathaniswa nezintambo ezivimbela ilangabi.
b. Izintambo ezivimbela ilangabi zishisa ingxenye yezinto ezibonakalayo kuphela kunezintambo ezivimbela ilangabi.
c. Izintambo ezivimbela ilangabi zibonisa izinga lokukhishwa kokushisa ingxenye eyodwa kwezine kuphela yezintambo ezivimbela ilangabi.
d. Ukukhishwa kwegesi enobuthi okuvela ekushisweni kuyingxenye yesithathu kuphela yalokho kwemikhiqizo engavimbeli umlilo.
e. Ukusebenza kokukhiqiza intuthu akubonisi mehluko omkhulu phakathi kwemikhiqizo evimbela ilangabi kanye nemikhiqizo engavimbeli ilangabi.
2. Izintambo Ezingenawo Umusi Ophansi Ezingenawo I-Halogen
Izintambo ezingenayo i-halogen ezinentuthu encane kufanele zibe nezimfanelo ezingenayo i-halogen, ezingenantuthu encane, kanye nezingashisi ilangabi, ngezincazelo ezilandelayo:
I-IEC 60754 (ukuhlolwa okungenazo i-halogen) I-IEC 61034 (ukuhlolwa komusi ophansi)
Ukuhanjiswa kokukhanya okunesisindo se-PH Ukuhanjiswa kokukhanya okuncane
PH≥4.3 r≤10us/mm T≥60%
3. Izintambo Ezingamelani Nomlilo
a. Izinkomba zokuhlola ukushisa kwekhebula elingashisi umlilo (izinga lokushisa lomlilo nesikhathi) ngokwezinga le-IEC 331-1970 ziyi-750°C amahora ama-3. Ngokusho kohlaka olusha lwe-IEC 60331 oluvela ekuvoteni kwakamuva kwe-IEC, izinga lokushisa lomlilo lisukela ku-750°C kuya ku-800°C amahora ama-3.
b. Izintambo nezintambo ezingashi zingahlukaniswa zibe izintambo ezingashi ezingashi ezingashi kanye nezintambo ezingashi ezingashi ngokusekelwe ekuhlukeni kwezinto ezingezona ezensimbi. Izintambo ezingashi ezifuywayo zasekhaya zisebenzisa kakhulu ama-conductor ambozwe yi-mica kanye ne-extruded flame insulation njengesakhiwo sazo esiyinhloko, kanti eziningi zazo ziyimikhiqizo ye-Class B. Lezo ezihlangabezana nezindinganiso ze-Class A zivame ukusebenzisa ama-tepi e-mica akhethekile kanye ne-mineral insulation (i-copper core, i-copper sleeve, i-magnesium oxide insulation, eyaziwa nangokuthi i-MI) izintambo ezingashi.
Izintambo ezivikelwe ngomlilo ezifakwe amaminerali azishi, azikhiqizi intuthu, azigqwali, azinabo ubuthi, azinawo umthelela, futhi zimelana nokufuthwa ngamanzi. Zaziwa njengezintambo ezingashi, zibonisa ukusebenza okuhle kakhulu kokuvikela umlilo phakathi kwezinhlobo zezintambo ezingashi. Kodwa-ke, inqubo yazo yokukhiqiza iyinkimbinkimbi, izindleko zazo ziphakeme, ubude bazo bokukhiqiza bunqunyelwe, irediyasi yazo yokugoba inkulu, ukuvikela kwazo kuthinteka kalula umswakama, futhi njengamanje, imikhiqizo eyodwa kuphela engu-25mm2 nangaphezulu inganikezwa. Kudingeka ama-terminal azinikele unomphela kanye nezixhumi eziphakathi, okwenza ukufakwa nokwakhiwa kube nzima kakhulu.
Isikhathi sokuthunyelwe: Septhemba-07-2023