Underground vs Ram Arm Motors: Which Automation Is Right?
Underground Motors
- Almost invisible once installed — only a small cover plate shows
- Gates appear to open by themselves, which is visually impressive
- Motor is protected from direct weather and vandalism
- Suits heritage properties where visible ironmongery would be wrong
- Significantly more expensive — typically £1,200–£2,500 per pair for motors alone
- Requires excavation and a concrete foundation box at the hinge point
- Service access means digging up the cover plate
- Water ingress is the enemy — drainage must be done properly or the motor fails
- Retrofit to an existing gate means removing the gate, digging the foundation, and rehanging
Heritage properties, conservation areas, high-value homes where visible motors would spoil the aesthetic, and new installations where the foundation work is done before paving.
Ram Arm Motors
- Much cheaper — £500–£900 per pair for good-quality motors
- Simple to install — typically a one-day job on existing gates
- Easy to service or replace — just unbolt and swap
- Arm design works with almost any pier width and gate type
- Less affected by ground conditions or drainage
- Visible on the pier, which some homeowners dislike
- Arm projects into the driveway or property and occupies space
- Exposed to weather and occasionally vandalism
- Heavy hardwood or wrought iron gates may need articulated arms instead of straight rams (£700–£1,200)
Most standard installations, retrofit jobs, budget-conscious projects, and properties where aesthetics are less sensitive.
The verdict
For retrofits on existing gates, ram arm motors are almost always the right answer — they are cheaper, faster to install, and easier to service. For new installations on premium or heritage properties where the motor will be specified from day one, underground motors justify their cost through the cleaner finish. The decision should be made before the piers are built, not after.
Drainage is the hidden cost
Underground motors fail when water sits in the foundation box. A properly installed system has a drainage channel, a sump, and ideally a soakaway connection. Skip this and the motor will flood within two or three wet winters. Any quote for underground motors that does not mention drainage explicitly is incomplete.
Force testing (both types)
Under BS EN 12453 every automated gate installation must be force-tested at commissioning, regardless of motor type. This is a legal obligation, not optional. Reputable installers carry a force gauge and provide a printed test certificate. If they do not, the install is not compliant.
Brand recommendations
The mainstream specialist brands — BFT, Came, FAAC, Nice — all make good motors in both formats. Avoid unbranded or rebadged units from general electrical suppliers, as spares become unobtainable within 5–10 years and the whole system becomes a replacement job rather than a repair.
Power supply requirements
Both motor types need a dedicated mains feed with a RCBO at the consumer unit. Running this cable from the house to the gate is often the biggest unknown in an automation quote — cable runs over 20 metres through paving can cost £800–£2,000 in electrician time alone. Confirm this is included or get a separate quote.
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