Commercial Electrical Fault Finding: Common Problems

 Electrical faults aren’t always as straightforward as a broken socket or a light that has stopped  working. Quite often, the difficult part isn’t repairing the fault — it’s actually finding out what is  causing it in the first place. 

We regularly attend faults where a breaker trips occasionally, equipment works perfectly when  we arrive, or a problem seems to disappear after being reset. These can be frustrating for the  person dealing with them, especially in a commercial environment where even a relatively small  electrical problem can interrupt work or affect other equipment. 

The aim with fault finding is not simply to get the power back on. It is to work through the  installation logically, identify the cause of the problem and make sure the repair is safe and  reliable. 

Why electrical faults can be difficult to find 

Some faults are obvious. A damaged accessory, burnt connection or failed piece of equipment  can sometimes be identified fairly quickly. 

Others are much less predictable.

An RCD or RCBO might trip once every few days. A machine may occasionally lose power. A  circuit could operate normally for hours before developing a fault. Heat, moisture, damaged  cables and even a particular piece of equipment only being used at certain times can all affect  how a fault presents itself. 

This is why simply arriving and resetting a breaker doesn’t necessarily tell us very much. 

The more information we can gather about when the fault happens and what is operating at the  time, the easier it becomes to start narrowing the problem down. 

Common electrical problems we investigate 

One of the most common calls we receive is for nuisance or repeated tripping. Sometimes the  protective device is doing exactly what it is designed to do and there is an underlying fault  somewhere on the circuit.

 We also investigate intermittent loss of power, damaged or overheating electrical equipment,  distribution faults and problems involving commercial or industrial equipment. 

On larger installations the fault may involve three-phase supplies, machinery circuits, distribution  boards or several circuits interacting with one another. 

These jobs usually require a slightly different approach to simply replacing a failed accessory. 

How we approach electrical fault finding 

We normally start by speaking to the person who has experienced the problem. This can often  provide some of the most useful information. 

Has it happened once or twenty times? Does it happen when a particular machine starts? Is it  worse when it rains? Has any work recently been carried out? 

From there we can inspect the installation and begin testing. 

Depending on the fault, this might involve electrical testing of individual circuits, checking  insulation resistance, testing protective conductors, checking earth fault loop values or  separating parts of the installation to narrow down where the problem is coming from. 

We don’t carry out every possible test on every fault. The idea is to use the information available  and work through the problem logically until the cause starts to become clear. 

Once a fault has been identified and repaired, we then test the affected part of the installation  again to make sure it is operating correctly. 

Resetting a breaker isn’t the same as repairing a fault 

This is something worth mentioning because it happens quite often. If an RCD, RCBO or circuit breaker trips and resets successfully, it is very easy to assume the  problem has gone away. 

Sometimes it may simply have been a one-off event, but repeated operation of protective  devices normally deserves investigation. 

They are there to disconnect the supply when certain electrical conditions occur. Continually  resetting one without understanding why it is operating can mean the actual problem is being  missed. 

This is particularly important in commercial premises where a developing fault could eventually  result in equipment failure or an unexpected loss of power. 

Commercial and industrial fault finding 

Commercial and industrial installations can present some particularly interesting faults because  there is often much more going on than in a typical domestic property. 

You may have several distribution boards, machinery, motors, contactors, three-phase  equipment and circuits supplying different areas of a building. 

A fault in one piece of equipment can sometimes appear to be a problem somewhere completely  different.

This is where systematic testing becomes important. Rather than changing parts and hoping the  problem disappears, we try to establish what has actually failed and why. 

It can take longer, but in our experience this is usually the quickest way of getting to a reliable  repair. 

Getting to the cause of the problem

Good fault finding is really a process of elimination. 

Start with what you know, gather as much information as possible, test the installation and  gradually narrow the problem down. 

Sometimes the answer is simple. Other times it can take considerably more investigation. 

Either way, the objective is the same: find the actual cause of the fault rather than just treating  the symptom. 

If you’re experiencing intermittent electrical problems, repeated tripping or equipment faults in a  commercial or industrial property, Sitwell Electrical provides electrical fault finding and maintenance across Rotherham, Sheffield and South Yorkshire