Cost fractions—typical electrical installation cost in process plants In an ordinary chemical plant, electrical installation cost is approximately:

Introduction / Context:
Heuristics for cost fractions help during early estimates (order-of-magnitude and study estimates) before detailed take-offs are available. Electrical installation cost is commonly expressed relative to purchased equipment or to total fixed capital investment (FCI).

Given Data / Assumptions:

• Conventional onshore chemical plant with typical power distribution needs.
• No unusual high-power electrochemical or arc-furnace duties.
• Historical percentages are being used for scoping accuracy.

Concept / Approach:
Industry references present electrical installation as about 10–15% of purchased equipment cost in equipment-based estimating, or roughly 3–10% of FCI in capital-based estimating. Both expressions are valid for preliminary budgeting and are reconciled by the typical ratio of purchased equipment to total installed cost.

Step-by-Step Solution:

Verification / Alternative check:
Check past project closeouts; the electrical package (cables, trays, MCCs, lighting, grounding) commonly falls within the cited ranges unless the plant is power-intensive.

Why Other Options Are Wrong:

• (a) alone or (b) alone do not capture that both are used in practice.
• “Neither” is incorrect because these are standard rules of thumb.

Common Pitfalls:
Applying these fractions to atypical plants (e.g., smelters, data centers) where electrical shares are much higher.

Final Answer:
either (a) or (b)