Option A:
- ask him to explain again to you, ask clearly and as slowly as needed for you to understand.
- write notes, draw diagrams, take pictures as your contractor explains
- it's within your right as customer/client
- if your contractor is genuine and honest when he initially tell you of these problems... he should not mind doing this
- with sufficient information... you can refine your online search better

Option B:
- seek consultation from another licensed wiring/chargeman

Energy Commission - Online System: Senarai Kontraktor Berdaftar-- https://ecos.st.gov.my/ms/web/guest/senarai...ktrik-berdaftar