Confusion about PAT testing (Portable Appliance Testing) is not uncommon. If you’re not sure exactly about what needs to be tested, don’t worry, you’re probably not alone.
One of the most common misconceptions about PAT testing is that portable appliances only need to be tested.
Portable Appliance Testing is a phrase that is a little confusing. It makes you believe that only portable appliances need to be tested when in fact it is recommended that anything with a plug is ‘maintained’ to ensure that it is safe.
These appliances come in different classifications such as Portable, Stationary, Moveable, Hand Held, IT and Fixed.
They all pose a different risk to the user of the appliance. For example if the appliance is portable then it generally gets moved around a lot and this means that it is prone to more damage than an appliance that does not. It may therefore need to be tested and maintained more frequently.
Here’s a more extensive breakdown of the different types of appliance out there as defined by the IEE and the code of practice for in-service inspection and testing of electrical equipment.
Stationary Equipment
If there’s one form of electrical appliance we trust, it’s the stationary ones. They sit there year after year not doing a whole lot until you need them, usually never moving from their comfortable spot.
Stationary equipment is basically things such as fridges, washing machines and other appliances that stay in a fixed position for most of their life cycle.
In terms of PAT testing, they are considered an extremely low risk for damage because they are hardly ever moved, meaning there’s not much chance at all of them becoming damaged.
Even so, it’s still important to test stationary equipment. A fridge that’s been moved slightly, for example, could have sustained damage to its mains cord, deeming it unsafe for use until repaired.
It’s therefore essential that during your PAT testing you don’t ignore equipment that’s stationary. It may look big and bulky and basically the opposite of portable, but stationary equipment is still part of the PAT testing procedure.
The frequency for the PAT testing of stationary appliances is dependent upon the environment that the appliance is used in. Combine this with the fact that the vast majority of stationary appliances are Class 1 such as Washing Machines, Fridges, Dishwashers, Vending Machines and Industrial machinery the recommended frequency can range from 3 months on a construction site (110 volt equipment) to 48 months in low risk environments such as offices and shops.
Information Technology (IT) Equipment
IT Equipment is considered slightly higher risk than stationary appliances however IT equipment is still relatively low risk because even though they can be moved, the vast majority of the time they actually aren’t.
This type of appliance basically refers to all types of business equipment such as franking machines, monitors, computers, printers and photocopiers and PC’s. They’re all eligible for PAT testing, and you should make sure they aren’t glossed over when making your list of what needs PAT testing.
After all, although they’re low risk, they’re still a risk as far as electrical safety is concerned. All computers are Class 1. Laptops are battery powered so they do not come under the requirements for PAT testing however the transformers that supply them do. The majority of laptop supplies are Class 1. Commercial / large office printers are always Class 1. The smaller home type of printer is generally Class 2 and can be seen by the figure of 8 lead connected into the rear of the printer.
Monitors again can be either fed from a transformer supply or can have an IEC lead directly into the back of the monitor.
The rules are relatively simple. If the equipment is fed from a low voltage power supply then the main area of concern is the power supply. The voltage that is generated from the low voltage side of the power supply is not seen as dangerous.
If the appliance has an IEC (Kettle Type) connector then the appliance is fed from 240volts and in these cases it is the appliance itself that needs to be tested.
When applying labels to the appliances after PAT testing you should either apply it to the transformer or in the case of an appliance not fed from a transformer apply the label to the appliance itself.
The frequency for testing IT equipment ranges from 3 months on construction sites (110 volt) equipment to 48 months in hotels.
Movable (Transportable) Equipment
Movable equipment refers to anything that usually sits in one place, but can be moved around quite easily. Many examples of movable equipment have wheels, but appliances like electrical fans and televisions also come under this bracket.
Movable equipment must be less than 18kg, and this type of appliances has a higher risk factor because they can be frequently moved around environments and can be damaged as a result.
The cables can be trapped and caught leading to flex damage. As moveable equipment has a slightly higher risk of damage the frequencies of electrical testing range from 3 months to 24 months depending upon the Class.
Portable Appliances
Yes, portable equipment actually comes under portable appliance testing as well!
NAPIT (the National Association of Professional Inspectors and Testers) say that a portable appliance is ‘any electrical item which can or is intended to be moved whilst connected to an energy supply’.
It’s easy to be confused about how portable and movable equipment differ from each other, as each is defined as being an easily movable item that’s less than 18kg in weight.
The main difference between the two, however, is movable equipment is usually more movable than portable equipment. While portable equipment can be moved (and as such is a high risk factor) movable equipment is more often transported around the environment, whereas portable appliances tend to stick around one area but can still be easily moved around that area.
Take, for example, a toaster. Usually sits in the kitchen, but the fact that it weighs under 18kg and can be moved makes it a portable appliance, as it’s quite easy to see how it could be moved by people making toast who either want a different toaster angle or just knock it accidentally.
Portable appliances should be tested between 3 and 24 monthly depending upon the environment that the appliance is in i.e School, Hotel, Offices and Shops.
Hand-Held Appliances
These items are the most important for PAT testing, as they have an incredibly high risk factor.
This is because hand-held items are much more likely to be damaged because of their direct interaction with humans who use them on a regular basis, meaning the likelihood of accidents is much higher.
For example, hand-held items such as power drills, angle grinders or even hair dryers are probably more than likely to be dropped at some point, or the cable feeding into the device could be damaged by over-stretching, be frayed by rubbing against something in the environment or damaged by a number of other factors.
This means that PAT testing of hand-held is equipment is extremely important. Visual inspections should be more thorough on these devices, as it is important to make sure they are fully safe for use.
How many times have you come across the lawnmower that has the electrical insulation tape wrapped around the cable? This is usually as a result of damage to the cable. How about the hair straighteners cable that is forever being burned by the heat from the appliance?
Hand Held appliances are the highest risk category. For this reason the vast majority of hand held appliances are Class 2. They have a layer of double or reinforced insulation which is an additional layer of protection for the user. However if the appliance gets wet this additional layer of protection becomes pretty much useless.
Hand Held appliances or any type of appliance which may be prone to the likelihood of damage should also be used in conjunction with an RCD device.
The frequency for testing again depends upon the area in which it is used however for Class 1 appliances it ranges between 3 to 12 months for Class 1 appliances however remember that there are not many hand held Class 1 appliances. The frequency for testing of Class 2 hand held appliances ranges from 3 months to not being required.
Don’t be complacent with hand held appliances especially in the home. Many accidents are caused by cables from this type of appliance. If you have damage to the cable then replace the appliance if you can afford to. It’s just not worth the risk.
Extension Leads, Cables, Chargers and RCDs
Extension Cables, IEC Leads and Cable reels are generally prone to damage from trapped doors and being dragged along floors. Long cables are also tripping hazards which should always be taken into account when running temporary supplies.
One of the biggest causes of fires is caused by using extension reels with high powered appliances whilst left coiled up. This causes the core of the extension reel to heat up and if using the reel with a high powered appliance such as a heater attached then this can cause electrical fires.
Whenever using an extension reel you should always unreel it especially when using it with a heater.
As cables are made from copper, temperature and length of cable has an effect on readings when carrying out Pat Testing. The longer the cable the higher the resistance will be. The smaller the cross sectional area of the cable the higher the resistance will be.
Here the nominal resistances at 20 degrees Celsius (Cables to BS6500)
| Nominal CSA | Nominal Conductor Resistance @20°c | Length (m) | Resistance (mohm) | Max Current Carrying Capacity (A) |
|---|---|---|---|---|
| 0.5 | 39 | 1 2 3 4 5 |
39 79 117 156 195 |
3 |
| 0.75 | 26 | 1 2 3 4 5 |
26 52 78 104 130 |
6 |
| 1.0 | 19.5 | 1 2 3 4 5 |
19.5 39 58.5 78 97.5 |
10 |
| 1.25 | 15.6 | 1 2 3 4 5 |
15.6 31.2 46.8 62.4 78 |
13 |
| 1.5 | 13.3 | 1 2 3 4 5 |
13.3 26.6 39.9 53.2 66.5 |
15 |
| 2.5 | 8 | 1 2 3 4 5 |
8 16 24 32 40 |
20 |
| 4 | 5 | 1 2 3 4 5 |
5 10 15 20 25 |
25 |
Whenever carrying out the earth bond test on a long cable or an appliance with a long cable the above must be taken into account.
The Pass mark for an appliance with a long cable would be 0.1ohms + cable resistance.
There are no specific guidelines regarding how often a cable on its own should be tested but the general rule of thumb is that if an appliance has a detachable cord you should test this at the same frequency as the appliance.
Fixed Equipment – Does it Need Testing?
Fixed equipment refers to anything that is fastened to a support, or secured permanently in a fixed location.
Such items include hand dryers, electric tower rails, cookers and central heating boilers. Many people believe that items such as this are exempt from PAT Testing. However you have the same risk of electrical shock from a piece of fixed equipment as you have a moveable or hand held. If the cable is damaged then you are still at risk of electrical shock.
If the ventilation holes are covered there is still a risk of fire or if the earth has been disconnected or removed from that cooker then there is a very real risk that someone will receive a shock.
Although the guidelines in the code of practice are a little vague the minimum that you should do as a duty of care is to visually inspect these appliances at the same time as carrying out your portable appliance testing.
As well as this it is good practice to ensure that the appliance is earthed if it is Class 1.
Any competent member of staff who has undertaken a training course should be able to do this.
Written by Barry Atkins
