(1) First-level nkyekyɛmu mfiri, a wɔbom frɛ no tumi kyekyɛ beae. Wɔde ahyɛ adwumayɛbea no substation no mfinimfini na wɔkyekyɛ anyinam ahoɔden mu kɔ kyekyɛ mfiri a ɛba fam-le mmeae ahorow. Saa level of equipment yi bɛn step-down transformer, enti anyinam ahoɔden parameter ahwehwɛdeɛ no korɔn na output circuit tumi nso yɛ kɛseɛ.
(2) Nkyekyɛmu mfiri a ɛtɔ so mmienu-level, a wɔbom frɛ no tumi kyekyɛ nkukuo ne motor control centers. Wɔde tumi kyekyɛ nkuku di dwuma wɔ tebea horow a adesoa no apete kakra na amansin kakraa bi na ɛwɔ hɔ mu; wɔde motor control centers di dwuma wɔ tebea horow a adesoa no yɛ kɛse na circuits pii wɔ hɔ mu. Wɔkyekyɛ anyinam ahoɔden a ɛwɔ ɔmansin bi a ɛwɔ soro-level kyekyɛ mfiri no mu kɔ adesoa a ɛbɛn no so. Ɛsɛ sɛ saa nnwinnadeɛ a ɛwɔ soro yi ma ahobanbɔ, hwɛ ne sohwɛ ma adesoa no.
(3) Wɔbom frɛ mfiri a wɔde kyekyɛ nneɛma a etwa to-level no sɛ kanea tumi kyekyɛ nnaka. Wɔn ne baabi a wɔde anyinam ahoɔden ma no ntam kwan ware na wɔyɛ mfiri nketewa-a ɛtumi kyekyɛ a wɔapete.