Ma'anar hasumiya na watsawa, masu watsa shirye-shiryen watsa shirye-shiryen suna tallafawa da sassan watsawa. Layukan wutar lantarki masu ƙarfi suna amfani da “hasumiya na ƙarfe,” yayin da ƙananan layukan wutar lantarki, kamar waɗanda ake gani a wuraren zama, suna amfani da “sandunan katako” ko “sandunan ƙanƙara.” Tare, gaba ɗaya ana kiran su “hasumiyai”. Layukan wutar lantarki masu tsayi suna buƙatar nisa mafi girma na aminci, don haka suna buƙatar kafa su a tsayi mafi girma. Hasumiya na ƙarfe ne kawai ke da ikon tallafawa dubun-dubatar layuka. Sanda ɗaya ba zai iya ɗaukar irin wannan tsayi ko nauyi ba, don haka ana amfani da sanduna gabaɗaya don ƙananan matakan ƙarfin lantarki.

Gabaɗaya akwai hanyoyi guda biyu don tantance matakin ƙarfin lantarki:

1.Pole lamba ganewa hanya

A kan hasumiya na manyan layukan wutar lantarki, yawanci ana shigar da faranti mai lamba, wanda ke nuna a fili matakan ƙarfin lantarki daban-daban kamar 10kV, 20kV, 35kV, 110kV, 220kV, da 500kV. Koyaya, saboda dogon lokaci ga iska da rana ko abubuwan muhalli, lambobin igiya na iya zama mara tabbas ko wahalar samu, suna buƙatar kulawa ta kusa don karanta su a sarari.

2.Insulator hanyar gane kirtani

Ta hanyar lura da adadin igiyoyin insulator, ana iya tantance matakin ƙarfin lantarki da ƙima.

(1) Layukan 10kV da 20kV yawanci suna amfani da igiyoyin insulator 2-3.

(2) Layukan 35kV suna amfani da igiyoyin insulator 3-4.

(3) Don layin 110kV, ana amfani da igiyoyin insulator 7-8.

(4) Don layin 220kV, adadin igiyoyin insulator yana ƙaruwa zuwa 13-14.

(5) Domin mafi girman matakin ƙarfin lantarki na 500kV, adadin insulator kirtani ya kai 28-29.