FAQs

Got questions about generators, hire, compliance or servicing? Find quick answers below, organised by topic.

Do your ATS units comply with building regulations for...

Yes. iPower's ATS units are manufactured to meet BS 8519 and BS EN 60947-6, which are the standards specified in building regulations and codes of practice for life safety systems in the UK and Ireland. We work with specifying engineers, M&E contractors and building control bodies to ensure full compliance.

How long does a mains failure to generator transfer take

For a standard ATS with a diesel generator: the ATS detects failure (typically with a 2–5 second delay to ignore momentary dips), sends a start signal, the generator reaches stable voltage and frequency (8–15 seconds warm, up to 30 seconds from cold), and the ATS transfers the load. Total elapsed time: typically 15–30 seconds. BS 8519 defines transfer categories from Category A (under 0.5 seconds — requires UPS) through Category D (15+ seconds — standard ATS and generator).

What is a make-before-break versus break-before-make ATS

Break before make (open transition): The existing supply is disconnected before the new supply is connected — a brief interruption occurs. This is standard for most standby generator applications. Make before break (closed transition): The new supply is connected before the old one is disconnected — a seamless, interruption-free transfer. This requires the two sources to be synchronised before transfer. Used where even a momentary interruption causes problems (certain UPS bypass arrangements, process-critical applications). iPower can supply either type.

What standards does iPower's ATS comply with

Our ATS units are designed and manufactured to comply with BS 8519:2010 (life safety power and control cable systems) and BS EN 60947-6-1 (low-voltage transfer switching equipment). These are the standards referenced in UK and Irish building regulations and M&E specifications for life safety applications.

What is a dual line bypass ATS and when is it specified

A dual line bypass ATS provides two independent bypass paths — one from the mains side, one from the generator side. This allows the ATS to be fully de-energised on all sides simultaneously, with the load maintained via the selected bypass path, without any dependency on a single bus arrangement. Specified for the most critical life safety installations — major hospitals, tier 3/4 data centres — where any compromise to supply continuity during planned maintenance is unacceptable.

What is a single line bypass ATS

A single line bypass ATS incorporates a bypass mechanism using a single bus arrangement. When the bypass switch is operated, the load transfers to the bypass path and the ATS can be isolated and worked on. Appropriate for most commercial and healthcare standby applications where a brief, controlled transfer to bypass mode is acceptable while engineers are present.

What is a bypass arrangement on an ATS and why is it needed

A bypass allows the ATS panel to be isolated and maintained without interrupting the supply to the load. Without bypass, any maintenance on the ATS itself requires a complete power shutdown — unacceptable in a hospital, data centre or any critical building. The bypass routes power around the ATS, allowing engineers to work safely while the building remains live.

What is the difference between a manual transfer switch...

A manual switch requires a person to physically operate it. An ATS detects mains failure automatically and transfers the load — typically within 10–30 seconds of mains failure, including generator start time. For any application where people cannot be present, or where power must be restored within seconds, an ATS is required.

Does iPower manufacture its own ATS units

Yes. iPower manufactures ATS panels in-house in Dungannon, from manual changeover switches to complex multi-bus automatic transfer switches with single or dual line bypass. Full in-house manufacture gives us control over specification, quality and lead time.

What is an Automatic Transfer Switch (ATS)

An ATS is a switching device that automatically transfers an electrical load from mains to a standby generator — and back again — when a power failure is detected. It monitors both supplies continuously and operates without manual intervention. For life safety buildings, a properly specified ATS is a regulatory requirement.