What is a Manual Transfer Switch? (MTS)

What is a Manual Transfer Switch? (MTS)

by | Nov 20, 2020 | Latest News & Articles

Scoping a diesel backup generator can be daunting, and you will often come across references such as ATS, MTS, and more acronyms – which if you are not familiar with can be confusing.

We recently published a guide on what ATS/AMF means in reference to a diesel generator, which you can read here. In this article, we are going to cover off what an MTS is, and an outline of how it works.

Here is a summary of the main acronyms for transfer switches/methods related to starting a generator.

What does MTS mean for a generator?

  • ATS – Automatic transfer switch
  • AMF – Automatic Mains Failure
  • MTS – Manual Transfer Switch
  • 2 Wire Start – A way of wiring a simple ‘on/off’ switch to your generator so you can start it up from a distance, or, in some instances this is required if you are using a generator in an installation with batteries and renewable energy sources.
UKC440ECO 440kVA Diesel Generator Main Image

These are the main ways to switch your generator on or off, and the most common setups for installing a system to switch your house, property or the load which you are trying to power from the mains supply to your backup standby generator.

How does a manual transfer switch work?

A Manual Transfer Switch, or MTS as it is shortened to, is a panel which gets installed after the meter on the outside of your property, but before your consumer unit (fuse board).

It is essentially a large switch, which has the mains power cables running into it, and also the cables from your generator.

When the mains power fails, it gives you a way to switch your property so it is running off the power generated by your backup diesel generator. It is a large switch, which normally has 3 settings – mains – isolation – generator. When the power fails, you turn the switch from mains to ‘off’ or isolation to make sure the connection is terminated, and then switch it to the generator setting. This means your home is now connected to the power cables running from your generator.

When the mains power returns, you do this in reverse order – switch the panel from generator to off/isolation, and then over to the mains setting so that your house is back on the mains supply incoming.

Unlike an ATS (automatic transfer switch), which doesn’t need any interaction, with an MTS you must ensure that you turn on your generator and let it come up to speed BEFORE you switch the panel over to feed your house from the generator. There isn’t a link between the MTS panel to ‘tell’ your generator to start or stop, this must be done manually. This is where a 2 Wire Start function comes in very handy…

Here is a illustration showing a typical setup of an ATS and MTS panel.

ATS Cropped 1

What is 2 Wire Start?

2 Wire start is a way to turn a generator on or off, using a simple switch, just like a light switch.

Almost all generators that have ‘ATS’ compatibility will also work on a 2 wire start system. All you need to do is run a simple on/off switch to the relevant ATS socket or terminals on your generator. This switch will act like an on/off switch for your generator, turning it on or off by completing a circuit when switched on.

These are really handy, as it allows you to run a small cable from the ATS port on your generator, to a suitable location and wire that cable to the switch.

When used with an MTS, you can install your manual transfer switch outside by your meter, and the on/off switch inside your house by the consumer unit.

As the generator will likely be installed some distance from your property, in the event of a power cut this means you can simply turn on the generator using the switch by your consumer unit (the 2 wire start set up), then wait for the generator to be up to speed, walk to the MTS panel and switch your property from mains to generator power.

Once the mains power comes back online, switch the MTS panel from the generator to mains, then inside your property, you can turn off the generator via the two-wire start switch.

If you are using a diesel generator with ATS compatibility to power your workshop or garage, a 2 wire start set up is great as you can install and position your generator in a suitable location, but run a cable from the ATS port, into your workshop and wire in a simple on/off switch for your lights/tools.

Simply turn on the generator, then use your appliances or tools. When finished, you can turn the generator off using the switch in your workshop.


Sometimes, this setup is preferred in backup situations as with a fully automated installation using an ATS/AMF panel, even in very brief short power cuts the ATS will fire up your backup generator when you may not want it to run, such as a brief power cut in the early hours of the morning when you would be asleep and not notice.

With an MTS you have full control over the start and stop procedure. An MTS set up is usually a more cost-effective solution too when compared to an ATS.

The downside is in the event of a power cut when you are not home, your generator will not start. This is not acceptable if you are using backup power systems due to exotic pets or for medical reasons when power at all times is essential.

To summarise

An MTS is a manual version of a switch, which changes your property from mains supply to generator supply in the event of a power cut. But, this switch must be changed manually.

Usually, if the generator is installed away from your property, a manual changeover switch will be installed alongside a 2 wire start switch to turn the generator on and off.

If you are looking for complete control over the use of your diesel genset, then an MTS is a cost-effective way to do this.

If you would rather not get involved, and have peace of mind that whenever the power fails, night or day whether you are home or not, then an ATS or auto-transfer switch set up would be best.

Every diesel generator we build or supply has ATS, AMF, MTS or 2 Wire Start compatibility. Browse our range of Cummins powered 3 phase generators, or single phase Evopowered sets to find the right generator for your needs.

About Genpower

Evopower generators are designed and distributed by Genpower Ltd, based in Pembrokeshire, Wales, UK.

Designing and building generators and power equipment since 2006 we have vast experience in the industry, which is shown in the high quality equipment in our ranges.

We are the sole distributor for Hyundai Power Products, P1 Power Equipment, Gardentek and we distribute Cummins powered gensets under our own brand Evopower.

With our large 120,000 sq. ft. distribution centre, offices and warehouse we hold a large amount of stock and have in-house technicians consistently working to improve our products, and expert sales, parts and aftersales departments available to answer any questions you may have, provide back-up and spare parts and – in the unlikely event something goes wrong, you can have piece of mind we are here to help. 

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