Concept:
Ceramic products are classified into different groups such as whiteware, heavy clay ware, refractories, glass, cement, etc. Heavy clay wares are generally large, coarse ceramic products made from common clay or shale.
Step 1: Heavy clay products are usually made from low-cost clay materials.
They are generally:
• coarse ceramic products,
• used in construction and drainage,
• fired at relatively high temperatures,
• mechanically strong and durable.
Step 2: Common examples of heavy clay wares include:
\[
\text{Bricks, roofing tiles, floor tiles, drain pipes, sewer pipes}
\]
Step 3: Now check each option.
Bone china is a fine whiteware product.
Electrical porcelain is a technical/whiteware ceramic product used for electrical insulation.
Sanitary ware is generally included in whiteware ceramics.
Step 4: Sewer pipe is a heavy clay product because it is a large, coarse ceramic product used in drainage and sewage systems.
Therefore, the product belonging to heavy clay ware is:
\[
\boxed{\text{Sewer pipe}}
\]