Mounting heights and installation types: details a quantity schedule must retain

Where to find mounting heights and installation methods

Mounting heights normally appear in the legend’s height column or the general notes. Examples include H=300 for ordinary outlets, H=1,100–1,200 above kitchen worktops and H=1,200 for switches. A separate note beside a symbol, such as H=1,500, overrides the default and should be retained in the remarks.

Flush or surface mounting is indicated by the legend’s item names (‘flush-mounted outlet’, ‘surface-mounted switch’) or symbol shapes (surface-mounted symbols often include an extra mark). Surface-mounted and waterproof types are often standard in unfinished areas such as underground parking, plant rooms and rooftops.

Why the same count can require different materials

• Box: A flush-mounted outlet box sits within the wall, while a surface-mounted box is attached to its face. The box items and quantities therefore differ.
• Plate/cover: Surface-mounted and waterproof devices use dedicated covers.
• Accessories: Surface-mounted conduit may require accessories such as saddles and connectors.
• Installation sequence and labor: Flush-mounted devices are installed before framing/finishing is complete; surface-mounted devices are installed after finishing, so their construction sequences differ.

A quantity schedule must preserve information needed for ordering and installation as well as count devices. The How drawing and order quantities differ begins with those distinctions.

How to record installation information in the schedule

Too many rows make the schedule cumbersome; combining rows can lose useful information. Use the following rules.

1. Row separation criteria: Use separate rows for distinctions that change part numbers, such as flush mounting, surface mounting and waterproofing.
2. Rules for recording remarks: Record details that affect installation but not the part number, such as mounting height, in the remarks. You can omit the default height and record only exceptions.
3. Identifier links: For a device with an exceptional mounting height, record its identifier, such as 101-K-07, in the remarks so it can be found again on the drawing.

This preserves the structure of a Reviewable Excel quantity schedule while retaining installation information.

Commonly missed exceptions

• Combining kitchen-worktop outlets with ordinary outlets without noting their different mounting heights
• Mistaking the entrance intercom or wall-panel height (around H=1,400) for the switch height
• Combining surface-mounted parking-area outlets with flush-mounted dwelling outlets in one row
• Missing lower switch-height exceptions in accessible units or units for older residents (for example H=900)

Mounting-height exceptions are often a single line in the general notes. Read those notes before counting.