• Description
  • Specs
  • Delivery

Make the most of your generator by adding a 250A automatic transfer switch (ATS) 3-Phase for added security and peace of mind. This mains to generator automatic changeover switch seamlessly detects a power outage and start your standby generator. As soon as mains power is restored the transfer switch turns off the generator and connects back to the mains power supply.

How Does a 250A Automatic Transfer Switch 3-Phase Work?

This transfer switch should be permanently installed close to the mains incoming supply to your building. In normal operation the load is supplying by the mains in the usual way but when the mains power is lost the ATS switch senses this loss and sends a signal to start your generator.

When the generator has started and is up to speed and frequency (normally around 8 to 10 seconds) this automatic changeover switch will automatically transfer the load to the standby generator set.

The automatic transfer switch will continually monitor the mains power and when this returns it will transfer the load back to the mains and initiate a cooling cycle and stop the generator. The transfer switch will then reset in readiness for the next power interruption.

General Specification of the 250A Automatic Transfer Switch 3-Phase includes:

  • 3 Pole mechanically & electrically interlocked pair of contactors.
  • Mains incoming input
  • Generator incoming input
  • Load output terminals
  • Mild steel enclosure
  • Bottom gland plate
  • Voltage monitoring relay for Mains supply
  • Over & under voltage protection of Mains supply
  • Panel status via LED indicators. Mains On Load, Plant On Load
  • Two wire start interface for generator control (starting &stopping)
  • Fuses for control & monitoring circuit protection
  • Generator warm up timer
  • Mains restoration timer
  • Full set of electrical schematics

Installation Note

The system is intended to be installed by a professional electrician with experience in standby power. Please contact Hampshire Generators if you need any assistance. Hampshire Generators can also maintain your generator with a regular cost-effective service plan or one-off visit. Simply call 01329 722390 or inquire via contact us page for more information.

Component Manufacture:

  • ABB

Amp Rating AC1:

  • 250 Amp


  • Industrial 3 Phase + N 415v

IP65 All Steel Enclosure:

  • Height 800 mm
  • Width 600 mm
  • Depth 300 mm


When will I receive my order?

In most cases, a product on our website will give you an indication of the current stock availability, but shipping is not uniform for all products. We maintain fantastic relationships with all of our suppliers and we aim to get products to customers within 3 business days of the order being taken. This availability is based on information from our suppliers and from sales and supply patterns. The availability information given is a guide only and not a guarantee as there are external factors that we may not have control over.

Coronavirus Update – UK couriers and transport companies will not currently guarantee delivery times and we are seeing a slight delay in deliveries – please bear this in mind when ordering.

Specialist Couriers – Some items such as the larger portable power stations are sent by specialist courier as standard couriers will not accept them. These specialist couriers are very reliable but sometimes don’t have tracking or timed delivery.

Split deliveries – We sometimes need to send orders for more than one item by different courier networks (portable power stations for example) – so you may receive items at different times.

1500rpm machines or larger diesel gensets however are typically priced on application and all depend on the destination. We will be happy to quote on any large diesel generator and discuss your needs over the phone or via email.

Most orders placed before 12pm on a business day will be shipped from our suppliers on the same day provided the product is in stock. If you need to be certain an item is in stock and available, or if you need a lead time, it’s worth calling our sales team on 01329 722390. Pricing for extended shipping areas like Northern Ireland, the Scottish Highlands and outlying Islands, Outer Hebrides, Channel Islands, Isle of Man, Scilly Isles, and other postcodes not considered as UK mainland can be obtained also by calling our offices.

Please note that the processing of a payment and acknowledgement email does not constitute a legally binding contact. In the case of mispricing, changes in stock quantity, or if we believe the machine will be misused, we reserve the right to cancel the order and provide a full refund.

Heavy Items

You will be contacted by phone after ordering a larger item to confirm a delivery date before your order is dispatched. Large or heavy items are dispatched through a pallet network, so if we can’t get in contact with you, we may be unable to send out your item on a next day delivery. Please be sure to include a working phone number with your order.

Heavy items will require the recipient to make arrangements to take delivery of the goods and may require the recipient to help the courier unload the item. For items that are delivered on a pallet the courier will leave the pallet as close to your door as possible.

1500rpm diesel generators will require forklift (or similar) offloading; if this is not available then we can arrange a Hiab offload at an additional price – please call us to discuss any delivery requirements.

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Product Details

250A Automatic Transfer Switch 3-Phase 400-415VAC

  • Use with standby generators for automatic start & load transfer
  • 250A – Suitable for generators 138kVA – 176kVA 3-Phase 400VAC
  • Complete with mains sensing and timers
  • Wall mounted enclosure with undrilled gland plates
  • Free delivery when ordered with a generator

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