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How An Automatic Transfer Switch Works

If you have a standby generator at your home for the purpose of providing you with electricity if / when the mains power goes down, you also require a transfer switch. The purpose of the transfer switch is to ensure that the mains power and the generator power are never connected. If the mains power came into contact with the generator, it would almost certainly burn out the generator.

If the generator is running and is connected to the mains it could back feed the mains and this would endanger the lives of electricity workers. There are two types of transfer switch, one being a manual switch and the other being an automatic transfer switch.

If you have a manual transfer switch, it follows that when the mains power goes down somebody has to manually switch over from the mains to the generator. Then it is also necessary for someone to start the generator in order to supply power to the house again. This is not too bad if you are at home when the power goes down, but if you happen to be away, you are not going to get any electricity into the home until you return and carry out the switching process, or the mains power returns. This may, or may not, be a matter of concern depending on whether you need to keep anything running all the time.

The Automatic Switch Is The Better Option

The alternative, and probably better option, is to have an automatic transfer switch. These do cost more than a manual transfer switch but, as the name suggests, switch from mains to generator automatically. When the mains power goes down, the switch will detect the lack of power and then send a signal to the generator telling it to start up. Once the generator is up and running, it will send a signal back to the transfer switch to tell it that it is operating, and the transfer switch will then switch off the mains contact and connect to the generator. Thus, the generator and the mains can never be connected.

The automatic switch means that when the power goes down you will only be without it for a few seconds, until the generator is up and running.

There is another option, and that is an ATS without mains detection. In this case the mains detection has to be built into the generator which will send a signal to the ATS to disconnect from the mains. The generator then starts itself and when running sends a signal to the ATS telling it to switch over.

Why Not Buy A Used Generator Instead Of New?

There is suddenly a considerable and growing interest in people looking for standby generators. Until recently, many people didn’t think of having one in their home unless they lived way out in the sticks where there were a number of outages when the power went down, and everything came to a grinding halt. Let’s face it: it isn’t funny when you suddenly have no electricity at 6.00 pm on a December evening. No light. No heat. And unless you have gas, you can’t cook either.

But over the last few months things have suddenly changed considerably. To begin with, the price of gas has gone through the roof, and with it is going electricity bills. Not only that, but the energy cap is going to be lifted in April and who knows where that is going to go?

Not Many Alternatives

Then there is the fact that in the UK we don’t have a lot in the way of alternatives. Instead of building new nuclear power stations, we are closing them! The green lobbyists have managed to see to it that fracking has gone out of the window, despite the fact that we have so much natural gas underground in the Northwest. We won’t go into the politics of that here, but it does seem to be very short-sighted. So, it seems that we have to rely on the generosity – or otherwise – of Mr Putin. Erm, right.

No wonder so many people have suddenly become interested in purchasing their own generator so that they can produce the electricity they need for their home, since it seems that things are only going to get worse, not better.

At Blades Power Generation, we have a huge range of different generators available, which can provide the sort of power that you need. It is important to get the right size and type of generator for your particular home, because there is no point in having one which is too big. Equally, you need one which will provide sufficient power.

But you don’t have to fork out a lot on a new generator if you don’t want to, because we also have used generators for sale.

If you buy one of our used generators you can have the backup that you need for your home when the power goes down, and you don’t have to spend a fortune. Obviously, our stock is constantly changing, so contact us to discuss your requirements.

Manual Changeover Switch Or Automatic? Which Is Best?

If you are considering buying a standby generator for your home, which in the light of recent events in the north many homeowners are looking at, there are a number of things to consider.

The first thing is to buy a generator which does what you want, because generators come in different sizes. One answer is to buy the largest size available in order to power the entire home, and if money is no object that could be one solution. However, if you want to buy a generator which only covers the essentials in order to keep costs down, then you will need to make an assessment of your home to purchase a generator which will cover only the essential electrical circuits.

However, sizing generators is not just a question of saying that your home is “x” square feet, so you need an “x” size generator. The complexity of your home’s electrical system also needs to be taken into account, especially if it has air conditioning. You will need an experienced electrician to calculate the electrical loads of your home and recommend he right size of generator.

Once you know this, you can then buy the generator and install it. However, there is also another issue, and that is how the generator starts when the power goes down. When this happens, it is necessary to switch from mains power to generator and it can be done using a manual changeover switch or an automatic one.

With a manual changeover switch you have to physically start the generator, and then when it is up and running one needs to switch from the mains to the generator. This means that there will be a delay while you do this. It also means that if the power goes down when you are not at home there will still be no power until you get back again. This may, or may not matter, depending upon what systems and equipment you use.

However, you can also get an automatic transfer switch. This is more expensive, but the way that it works is that when the power goes down the switch will send a signal to the generator telling it to start up. When the generator is running it will send a signal to the ATS telling it to switch over. When the mains power is restored, the ATS will switch off the generator and transfer back to the mains.  

Storm Arwen Caused Havoc in the North

Investing in a standby generator for your home is not going to be cheap, but in the light of recent events there will no doubt be many homeowners who would never have considered it before but are now studying the market to find a generator that will cover them for a power outage.

Storm Arwen - only the first named storm of this season – has caused havoc for people in the north, some of whom have been without power for 11 days. Many of them have had no lighting and no TV, so not only have they had no power but have not been able to keep up with the news and see when (if ever!) their power is going to be restored. The worst part of it for those people is that in most cases they have had no heating either – in the freezing conditions caused by the storm.

It is bad enough having a power outage in your home, but in other situations it can literally be a matter of life or death. In a hospital, for instance, the loss of power for even a few seconds can be a catastrophe. So, under those circumstances, the installation of a standby generator is not an option, but an essential.

Then there is the matter of how the generator kicks in when the power goes down. This is taken care of by a transfer switch, and it can either be manual or an automatic transfer switch.

With a manual transfer switch, as you might imagine, you have to start the generator yourself and then when it is up and running switch over from the mains input to the generator. This means that there will be a time gap between the power going down and the generator producing power again. It also means that if you are not at home or on the premises, the power will be down until someone can start the generator.

An automatic transfer switch, however, does the job for you. It senses when the power has gone down and sends a signal to the generator to start up. When the generator is running it will send a signal back to the automatic transfer switch which will then switch over from the mains to the generator. When the power returns from the mains, the switch will turn off the generator and return to mains power again. 

Should You Buy A Generator For Your Home?

Should you buy a standby generator for your home? Well, the answer to that is “it depends”. To some extent it may be a matter of choice. For instance, for some people, suffering from a blackout on one occasion may be sufficient reason to get a generator.

However, if you live in an area where power outages are frequent (i.e., more than three a year) or they last for several hours, then investing in a standby generator is more a matter of necessity rather than simple convenience.

Generators are available in a range of different sizes and can be powered by diesel, propane, or LPG. Whether diesel generators will be available for much longer in the UK remains to be seen. One option is to buy a generator that is big enough to power the whole of your home, and if you can afford it you might want to do just that. However, another option, which is more affordable, is to buy one that powers your most essential electric circuits. You would need an experienced electrician to calculate the anticipated electrical loads of your home in order that he could recommend the correct size.

You will also need a transfer switch to transfer the power supply from the mains to the generator and back again when the mains power is restored. This can either be a manual transfer switch or an automatic one.

The disadvantage of a manual transfer switch is that someone has to be on the premises in order to transfer from one to the other. It rather depends on what sort of equipment you need to power. If there is always someone at home, it is not so much of an issue, but if you need to be able to switch to the generator instantly at any time, then an automatic transfer switch is the answer.

This will detect the fact that the mains supply has gone down and send a signal to the generator to start up. When the generator has started it sends a signal back to the automatic transfer switch which will then switch over to the generator. When the power is restored, the automatic transfer switch will transfer back to the mains and switch the generator off.

Certainly, an automatic transfer switch is more expensive to install than a manual one, but once you have it, you have no worries.

Why An Automatic Changeover Switch Is Best For Use With Your Generator

More people today are investing in a standby generator for their homes because of the possibility of power cuts. If you live out in the sticks somewhere, you may find that you have power outages on a regular basis, and this can range from being a minor inconvenience to something far more serious, depending upon what sort of equipment you have and use that requires electric power.

For instance, you might have a family member dependent upon a power wheelchair, a ventilator, or communication devices that rely upon electric power, so if you are unable to charge them it can be a serious issue. OK, if the power goes down for a couple of hours it may not be too serious a matter, but if it goes down for a day or even more, then it is a big issue. Even if you only have a power outage three or four times a year,that is three or four times too many.

This is why more people are buying generators so that they can always have a supply of electricity, no matter what. However, when you have a generator, it is a legal requirement that you also have a transfer, or changeover, switch. You can install either a manual or an automatic changeover switch.

An automatic changeover switch is always preferable because - believe it or not – when the power goes down your system will automatically start the generator and so you will only be without power for a matter of a few seconds until the generator kicks in. If you have a manual changeover switch it means that somebody has to manually switch from the mains power to the generator. That may be OK if someone is on the premises and can do that, but if you are away from home for a couple of days and you have something such as a tropical fish tank, those fish are, unfortunately, not going to last until you get home.

With an automatic transfer switch, you have no such worries. You can have an automatic transfer panel with mains detection or without. If it has mains detection, it will detect the power failure and send a signal to the generator telling it to start. Once the generator has started, it will send a signal back to the automatic transfer switch to tell it that it is ready, and the transfer switch will then disconnect from the mains and connect to the generator.

Manual Changeover Switch -V- Automatic. What’s The Difference?

If you have an emergency generator the good thing is that every time there is a power blackout you can start up your generator and, literally, switch the lights back on.

The way that your generator is turned on can be either manual or automatic and it can be done using a changeover switch, also known as a transfer switch. In fact, it is a legal requirement that if you have a standby generator, you have to have a changeover switch.

This is for two main reasons. It separates the power from the two different sources. You can either have power from the mains or you can have power from the generator, but not both, at the same time.

If you did not have a changeover switch and you started your generator and then the mains came back on again while the generator was running it would almost certainly burn your generator out. The other way around, it prevents the generator feeding power back into the mains when electricity workers are trying to restore the power, which could endanger their lives.

What’s The Difference?

So, what is the difference between a manual changeover switch and an automatic one? Well. think of it as of the gearbox in your car. It can either be manual or automatic. If you have a manual gearbox, every time you want to change gear you have to depress the clutch, shift the gear lever, and let the clutch out again. If you have an automatic gearbox, it does all that for you.

A manual changeover switch means that you have to switch over by hand. You also have to start the generator, which is probably in the garden, and it could be pouring with rain! In fact, it very likely would be, because the power often goes down as the result of a storm.

An automatic changeover switch detects that the mains power has gone down, switches over, and starts the generator automatically.

You are far better off with an automatic changeover switch because there is no time delay. When the power goes down you will be back up and running in seconds. You don’t get wet in the pouring rain. It also works when you are away from home. If nobody is at home and you need the power on and have a manual switch, that power is going to stay off until you return.

There is only one advantage to having a manual switch and that is that it is cheaper to purchase. That aside, there is no contest.

Do You Need A Standby Generator?

The answer to that question is “it depends”. A emergency generator is not a cheap item, but if you have a power blackout it will kick in within seconds and bring power back into your home.

To some extent, whether or not you need an emergency generator is a matter of personal opinion. For some people, even suffering a single power outage can justify the expense, but if you live in an area where there are frequent blackouts or out in the country in a remote area, then a standby generator is more of a must. 

There is also the fact that we are heading towards the use of electric vehicles becoming far more common. While that may be a good thing for the environment, it also means that a lot more people will be charging up batteries. So, you could see a huge surge in the amount of power required at the end of the working day when people get home and plug in their car to charge it. That may well lead to more and more power outages.

What Is The Best Type Of Generator?

So, what is the best emergency power source in the UK? Well, there are two types of generator, those powered by diesel, or they can be powered by natural gas or LPG. They can also be air cooled or liquid cooled. Air cooled are generally less expensive, and smaller, but they are also louder than liquid cooled generators.

You also need to consider the size of generator that you require. A common mistake is to buy the biggest that you can in order to power the whole of the home. In many cases, it would be more sensible and less expensive to buy a generator that produces sufficient power to run the essential circuits in your home – lighting, heating, cooker, water heater, security system if you have one, and the TV and laptop. Also, your electric vehicle if you have one, so that you are not trapped at home.

When you are looking for the best emergency power source in the UK you need to calculate the anticipated electrical load, and you really need an experienced electrician in order to do this. You want a generator that will provide you with the power that you require, but you need to consider the expense involved since there is no point in having a generator that is too large.

Reasons Why You May Wish To Consider A Standby Generator

An emergency power source in the UK is an independent source of electrical power that can provide security and safety to important electrical systems and apparatus in the event of the mains supply failing for one reason or another. A standby power system can include batteries, a power generator, and so on, and they are there to protect life and property in the event of the mains power supply being broken. 

Places such as hospitals rely on a constant supply of power in order to provide medical support to patients and to be able to continue an operation if, for instance, the mains power supply fails in the middle of the procedure. Other places which rely on a constant supply of electrical power include scientific laboratories, computer systems, telecoms, radio and TV stations, and many more.

We also want a constant supply of electricity in our homes. This may not be a situation which is life-threatening, but it can be a nuisance if electric power goes down in the middle of cooking a meal or even just watching a programme on the TV.

 

More Homeowners Are Considering Installation Of A Standby Generator

This is why more and more homeowners are considering the installation of a standby generator so that everything can run as usual even if the mains power is not available. For instance, a homeowner may also be a lover of tropical fish, and these could be lost if mains power is not available for several hours and the water in the tank goes too cold. An emergency power source in the UK in the form of a standby generator can kick in almost instantly when the mains power goes down, especially if an automatic transfer switch is in operation.

Indeed, a transfer switch is a legal requirement if you have a standby generator because there could be danger to electricity supply employees endeavouring to restore power, and there is also a risk to the generator if there is no transfer switch.

Mains power can be lost for a number of reasons, often because of downed lines as a result of poor weather. However, there may also be a malfunction at a sub-station, planned downtime for repairs, or even a grid-wide failure.

Emergency backup can include batteries, and some larger buildings have a gas turbine, but this can take between five and thirty minutes to achieve full power. So, a standby diesel generator is the most common form of backup in the event of mains failure. 

Importance of an Automatic Transfer Switch

If you have a standby generator at your home so that you can still generate electricity when the power fails, then the law requires you to have a transfer switch. This is the case in every country when installing a generator at a property with a mains supply. It can either be a manual transfer switch in the UK or an automatic transfer switch. It doesn’t matter which, but you must have one or the other.

The reason is actually quite simple. When you have a transfer switch it will prevent the generator from back feeding the mains when it has gone down which would put the lives of electricity workers in danger while they are attempting to restore power. It is also good for your generator because it stops mains power from coming into contact with it, which would almost certainly burn out your generator.

One advantage of a manual transfer switch in the UK is that it is cheaper to buy and install than an automatic transfer switch. However, it means that you have to switch it over manually, obviously, which means that there will be a delay in the power supply to your home or business premises.

 

Somebody Needs To Be On The Premises

Not only that, but it also means that somebody needs to be on the premises at the time the mains goes down. In some instances, this may not be much of a problem, but could cause issues if you need a constant supply of power. With an automatic transfer panel, the generator will start up automatically whether you are there or not.

Automatic transfer switches come in a variety of designs, but typically a mains failure relay is fitted in an electrical enclosure, with two contactors. These are electrically and mechanically interlocked so that they cannot both be closed at the same time. The contactors need electric power in order to close.

The mechanical interlock should stop both contactors closing at the same time, but the electrical interlock provides extra protection. A normally closed contact is fitted to each contactor and when the contactor is energised, they open. If you have two contactors, A and B, the circuit to close contactor A is wired through the auxiliary of B. Therefore, when B is closed, it is not possible to energize A. The same is true for B, which is wired through the auxiliary of A. This provides the electrical interlock.

What happens is that when the mains fails, the ATS will send a signal to the generator and when it is up to full power the ATS will open the mains contactor and close the generator contactor. When the mains returns, the generator contactor is opened and the mains contactor is closed. This means that there will always be a short break in the power supply when changing over.