How to Safely Reset a Breaker and Fault Find | Faithful Spark Electricians

Why Has My Circuit Breaker Tripped — and What Should I Do?

You flick the kettle on, the lights go out in half the house, and suddenly you are standing in the dark wondering what just happened. It is one of the most common calls we receive here at Faithful Spark Electricians, and the good news is that in many cases you can safely reset a tripped breaker yourself — as long as you know what you are doing and when to stop.

This guide walks you through exactly what causes a breaker to trip, how to reset it correctly, how to track down the fault, and — just as importantly — when to put the kettle down and pick up the phone instead.

We cover Scottish homes and businesses across Aberdeen and Aberdeenshire, and everything in this post is written to reflect current BS 7671 wiring regulations and Scottish Building Regulations. There is no BS 7671 here — that applies only in England and Wales.

What Actually Happened? MCB Trips vs RCD Trips Explained

Before you go near the consumer unit (the grey or white box on your wall — often still called a fuse box, though modern versions contain circuit breakers rather than fuses), it helps to understand what type of device has tripped and why. The two are quite different.

MCB — Miniature Circuit Breaker

An MCB (Miniature Circuit Breaker) protects each circuit against overcurrent and short circuits. An overcurrent happens when too many appliances are running at once and the combined current draw exceeds what the circuit is rated for. A short circuit is more dramatic — it occurs when a live conductor comes into direct contact with a neutral conductor, causing a sudden surge of current. Both situations will cause the MCB to trip almost instantly.

On a tripped MCB, the switch will be in the down position rather than firmly up.

RCD — Residual Current Device

An RCD (Residual Current Device) works differently. It monitors the balance of current flowing out on the live conductor and returning on the neutral. If those two values differ by as little as 30 milliamps — suggesting current is leaking to earth, possibly through a person or a fault in the wiring — it trips within milliseconds to prevent a potentially fatal electric shock.

RCDs are life-saving devices. When one trips, it is telling you there is an imbalance somewhere. That might be a faulty appliance, damp getting into a fitting, or a problem with the fixed wiring.

RCBO — The Best of Both

A modern full RCBO consumer unit contains one RCBO (Residual Current Breaker with Overcurrent protection) per circuit. An RCBO combines the functions of an MCB and an RCD into a single device. This means if one circuit develops a fault, only that circuit trips — the rest of the house stays on. This is far superior to older split-load boards where a single RCD covers multiple circuits, meaning one faulty toaster can knock out the lights in several rooms at once.

If you still have an older split-load arrangement, it is worth reading about a consumer unit upgrade — but that is a separate conversation.

How to Safely Reset a Tripped Circuit Breaker or RCBO

Right. You have had a look inside the consumer unit and identified which breaker has moved out of position. Here is how to reset it correctly.

Resetting an MCB or RCBO

1. A tripped MCB or RCBO will be in the down position. Simply push it firmly back up to ON.
2. If it holds — great. If it trips again immediately, there is still an active fault on that circuit. Do not keep resetting it repeatedly. Continued resetting with a live fault risks damage to your wiring and, in serious cases, fire.

Resetting an RCD

1. Locate the RCD — it is usually a wider switch with a small TEST button on it.
2. Try pushing it firmly back up to ON. Some RCDs will reset directly from the tripped position without any issue.
3. If it will not latch, push it fully down to OFF first, then push it back up to ON. Certain models need that full down movement before the mechanism will engage.
4. If it holds — good. If it trips again straight away or simply will not stay on, do not keep trying. There is a fault present that needs investigating.

A word of comfort: modern consumer units are designed to be safe for homeowners to operate in this way. You are not doing anything dangerous by pressing a switch. The danger comes from repeatedly resetting a breaker that keeps tripping, or from working inside the consumer unit itself — which you should never attempt.

How to Fault Find After a Trip — Step by Step

The breaker has reset but you want to know why it tripped in the first place. Here is a systematic approach that any homeowner can follow safely.

Step 1 — Unplug Everything on the Affected Circuit

Before you reset the breaker again, unplug every single appliance connected to that circuit. For a ring main (sockets circuit), that means going room by room and pulling plugs. Do not just switch appliances off at the plug — physically unplug them.

Step 2 — Reset the Breaker with Nothing Plugged In

With nothing connected to the circuit, reset the MCB or RCBO as described above. Now watch what happens.

• If the breaker holds with nothing plugged in — the fault is almost certainly in one of your appliances rather than the wiring itself. Move to Step 3.
• If the breaker trips again immediately with nothing plugged in — the fault is in the fixed wiring. This is not something you should attempt to investigate yourself. Contact us and we will carry out a proper fault-finding inspection.

Step 3 — Plug Appliances Back In One at a Time

With the circuit live and holding, plug your appliances back in one at a time with a short pause between each. Switch each one on and give it a moment. The one that causes the breaker to trip again is your culprit.

Once identified, leave that appliance unplugged and do not use it until it has been checked or replaced. A faulty appliance can be a genuine safety hazard — not just a nuisance.

A Note on RCD Trips Specifically

If it is an RCD that keeps tripping, the cause is earth leakage somewhere. This can be a faulty appliance with damaged insulation, a light fitting that has had water get into it, or a problem in the wiring itself. The same process applies — unplug everything and see if the RCD holds. If it does, work through the appliances one by one. If it still trips with nothing connected, there is a wiring fault and you need a qualified electrician.

Electrical Safety First has a helpful guide on RCD testing and why these devices matter so much — well worth a read.

When to Stop and Call an Electrician

There are situations where the right thing to do is step away from the consumer unit entirely and get a professional involved. Please do not push on if any of the following apply.

• There is a burning smell anywhere near the consumer unit, sockets, or appliances. Burning insulation has a very distinctive, acrid smell. If you notice it, do not reset anything.
• There are scorch marks or discolouration around the consumer unit, a socket face, or a switch plate.
• The consumer unit or any switch feels hot to the touch. Electrical components that run warm under normal load are not uncommon, but hot is different.
• The breaker trips again immediately after reset with no appliances on the circuit. This points to a wiring fault that requires testing equipment to diagnose properly.
• There is any sign of water ingress near the electrical installation — a leak, flooding, or condensation inside a fitting. Water and electricity is a serious combination. Switch off at the consumer unit and call us before switching anything back on.
• The breaker has tripped more than twice in a short period for no obvious reason.

Our team covers Aberdeen and Aberdeenshire, and we carry out full electrical fault-finding as part of our service. If you are unsure about what you are looking at, it genuinely does not cost anything to ask. Reach us on 07304 027013.

The Health and Safety Executive guidance on electricity is also clear that electrical work beyond basic operation of your own consumer unit should be carried out by a competent person — and for any work that requires certification, that means a registered contractor.

Old Consumer Units and Fuse Wire — What Not to Do

Not every home in Aberdeenshire has a modern consumer unit. Older properties — particularly those that have not had rewiring work done in several decades — may still have a consumer unit that uses rewirable fuses rather than circuit breakers. These look quite different: instead of a bank of switches, you will see a row of ceramic fuse holders, each containing a length of thin fuse wire.

When one of these fuses blows, the temptation can be to simply replace the fuse wire and carry on. Please do not attempt this yourself. Here is why:

• Using the wrong gauge of fuse wire — even slightly too thick — means the fuse will no longer provide protection at the correct current level. It may allow a fault to persist that it should have interrupted.
• Rewirable fuses provide no RCD protection whatsoever, meaning there is no automatic disconnection in the event of earth leakage or a shock risk.
• The presence of old rewirable fuses almost always points to an installation that is significantly out of date in other ways too.

If your property still has this type of setup, the honest advice is that it needs replacing. A modern full RCBO consumer unit provides significantly better protection for the occupants, and in many cases it will be required before any additional electrical work can be certified under Scottish Building Regulations.

You can find out more about what is involved in our guide to consumer unit upgrades in Aberdeen, or get in touch and we will be happy to talk it through with you.

If your property has not had a full electrical inspection in a while, an Electrical Installation Condition Report (EICR) in Aberdeen is the proper way to assess the overall condition of the installation. It covers everything from the consumer unit to the wiring throughout the property, and it will identify any items that need attention.

The Monthly RCD Test — a 30-Second Check Worth Doing

This is a quick tip that most homeowners never do, but should. BS 7671 (the UK wiring regulations) recommends that you press the TEST button on each RCD or RCBO in your consumer unit once a month.

Here is what to do:

1. Make sure any sensitive equipment — computers, televisions, anything mid-process — is switched off or saved first.
2. Press the small TEST button on the RCD or RCBO.
3. It should trip immediately. If it does not trip, the device may have developed a fault and needs to be inspected by an electrician.
4. Reset it by pushing it to OFF and then back to ON.

It takes under a minute and it confirms the device that protects you from electric shock is still working correctly. It is also an opportunity to glance at your consumer unit and check that everything looks normal — no scorch marks, no unusual smells, all breakers in the ON position.

Is Your Electrical Installation Up to Date?

If you are frequently dealing with tripping breakers, it may be a sign that your installation is working harder than it should — or that something more fundamental needs attention. Older properties in Aberdeen and Aberdeenshire often have wiring and consumer units that were installed decades ago, and the demands placed on domestic electrical systems have increased enormously since then.

A periodic electrical inspection — an EICR — will give you a clear picture of the current condition of your installation and flag anything that needs attention before it becomes a problem. If the installation is found to be significantly out of date, a full house rewire may be the right solution, particularly in older properties.

Any work requiring an Electrical Installation Certificate we carry out is certified under Scottish Building Regulations. You can read more about the Electrical Installation Certificate process in Scotland if you want to understand what certification involves and why it matters when you come to sell your property.

As a NICEIC Approved Contractor (enrolment 620239), all of our work is independently assessed against the relevant British Standards. That is not something every electrician you will find can say.

Frequently Asked Questions

Why does my breaker keep tripping?

Repeated tripping is almost always telling you something. It could be that one circuit has too many high-draw appliances running simultaneously (an overload), a specific appliance has developed a fault, or there is a problem developing in the fixed wiring. If a breaker trips repeatedly even after you have removed all appliances from the circuit, stop resetting it and get a qualified electrician in to investigate. Repeated resetting without identifying the underlying cause is not safe.

Can I reset the breaker myself?

Yes, in most straightforward situations. Resetting a tripped MCB or RCBO by pushing it to OFF then back to ON is something any homeowner can do. The same goes for pressing the TEST and RESET button on an RCD. You should stop and seek professional help if the breaker will not hold after reset, if there are any signs of damage or burning, if the unit feels hot, or if there is water anywhere near the installation.

What if the breaker trips again straight away after I reset it?

If the breaker trips immediately after reset — before you have even plugged anything in — there is an active fault on that circuit. Do not keep resetting it in the hope it will clear. Leave the breaker in the tripped position and call an electrician. The fault needs to be found and fixed before the circuit is live again.

What is the difference between an MCB trip and an RCD trip?

An MCB trip means there was too much current on that circuit — either through overload or a short circuit. It is protecting the wiring from overheating. An RCD trip means there is a leakage of current to earth — this is the device that protects people from electric shock rather than protecting wiring. The fault-finding process is similar for both, but an RCD that trips repeatedly with nothing plugged in is particularly important to get checked out, as earth leakage faults in fixed wiring can be a serious hazard.

When should I call an electrician rather than resetting myself?

Call a qualified electrician if: the breaker trips again immediately with nothing connected to the circuit; you notice any burning smell, scorch marks, or heat near the consumer unit or any socket; there has been water ingress near any part of the electrical installation; or you have an older property with rewirable fuses rather than circuit breakers. Any of those situations requires professional investigation rather than self-help resets.

Need Help? Get in Touch with Faithful Spark Electricians

If you have worked through the steps above and something is still not right — or if you would simply rather have a qualified electrician take a look — we are based in Peterhead and cover Aberdeen and Aberdeenshire. We hold City and Guilds qualifications (2357, 2365, 2391-52) and an HNC in Engineering Systems, and as a NICEIC Approved Contractor our work is independently verified.

Give us a call on 07304 027013 or visit our contact page to get in touch. We are happy to advise even if it turns out to be something you can resolve yourself.