Dimensions of a 25-position concealed electrical box

A 25-position concealed electrical box is typically a large multi-gang box, with dimensions roughly 72–80 inches in width, 4–6 inches in height, and 3–5 inches in depth, depending on manufacturer and internal volume requirements.Estimating Size for a 25-Position BoxElectrical boxes are sized based on the number of device positions (gangs) and the internal volume needed for wiring and components . A 25-position box is considered a very large multi-gang configuration, often used for centralized control panels, multiple switches, or complex junctions. Standard multi-gang boxes increase in width with each additional position, while depth is critical for wire fill and safety .Width: Each gang typically requires 1.5–2 inches of width. For 25 positions, the total width is approximately 37.5–50 inches. In practice, manufacturers may provide modular or sectional boxes to achieve this width without creating a single unwieldy unit .Height: Standard wall-mounted boxes are usually 4–6 inches tall, sufficient to accommodate device height and wiring clearance .Depth: Depth is crucial for wire fill. For high-density boxes like a 25-position unit, 3–5 inches is common, with deeper boxes preferred for multiple conductors and complex terminations .Internal Volume ConsiderationsInternal volume is measured in cubic inches and must comply with NEC wire-fill guidelines. A 25-position box may require several hundred cubic inches to safely house conductors, connectors, and devices . Using a deeper box or modular sections helps prevent overcrowding and allows for future expansion .Material and Installation NotesMaterial: Metal (steel) or PVC boxes are common. Metal boxes allow thinner walls, maximizing internal volume, while PVC boxes have thicker walls but are easier to cut and install .Concealed Installation: For recessed or concealed applications, ensure the box fits within wall studs and allows for mud rings or plaster rings if needed .Custom Fabrication: For very large multi-gang boxes like 25 positions, manufacturers often provide custom or sectional enclosures to meet exact dimensions and code requirements .SummaryA 25-position concealed electrical box is a large multi-gang unit, typically modular, with approximate dimensions: width 37–50 inches, height 4–6 inches, depth 3–5 inches, and internal volume sufficient for safe wire fill. Always verify manufacturer specifications and NEC compliance before installation to ensure proper fit, safety, and future expandability .