One Lightning Strike, One Power Trip: Could Your Office Survive It?

Offices that do not survive a lightning storm usually fail in one of three ways: a surge damages equipment, a voltage dip resets it, or a power trip switches everything off with unsaved work and open connections. Surge protection handles the first, and a UPS (uninterruptible power supply) of the right type handles all three for the equipment plugged into it.

Below: lightning season in Singapore, surges versus dips and outages, UPS designs compared and what to protect first, with store examples: the Targus Smart Surge 4 Plus, APC Back-UPS Pro BR 900VA, Eaton 5SC 1000VA and APC Easy UPS On-Line SRV 2000VA.

Which power problem does what, and what stops it?

How often does lightning happen in Singapore?

Often enough to plan for. The Meteorological Service Singapore (MSS) publishes 1991 to 2020 monthly means for Changi: lightning days range from 4 in February to 22 in November, and adding up the twelve monthly means gives about 175 lightning days and 167 thunderstorm days a year. MSS notes that in the inter-monsoon periods, late March to May and October to November, thunderstorms, "at times severe", occur in the afternoon and early evening, in the middle of the working day. A storm during office hours is routine, so design power protection for it rather than improvising after it.

Surge, dip or power trip: what is the difference?

A surge is a very short rise in voltage. Eaton notes that most surges start inside buildings from normal electrical activity, and lists lightning, power restoration after an outage, switching on large appliances and tripped breakers among the causes. A voltage dip is, in the Energy Market Authority's (EMA) words, a momentary reduction in supply voltage that does not lead to power failure. EMA says occasional dips can happen in any supply system; one can reboot a desktop or drop a call. A power trip or outage is a loss of supply, from a breaker on your floor or the wider network.

EMA cites a benchmarking study that found Singapore has an average interruption time of less than one minute per customer a year. So the grid is rarely the weak point; the office usually is: a desktop on a bare wall socket, a firewall on a power strip, a switch in a cupboard with no backup. For a suspected supply issue, EMA points consumers to SP PowerGrid's 24-hour Electricity Service Centre on 1800 778 8888.

What does a surge protector actually do?

A surge protector absorbs short spikes. Its joule rating, as Eaton explains, measures how much energy it can absorb before it fails, and Eaton suggests 1,000 joules or higher for sensitive electronics. Protection also wears out as the components absorb repeated surges, so an old strip is not the same as a new one. The Targus Smart Surge 4 Plus with USB-C PD Port (S$43.92) has four outlets, a 30 W USB-C port, 1,440 joules of surge protection, a status LED and a grounding warning light that shows when the wall socket is not properly earthed, which is a useful check before you trust any protection.

Three limits matter. A surge protector does nothing during a dip or outage. Surges can also enter through Ethernet, telephone and coaxial cables, which Eaton notes many surge protectors now cover. And where the risk is higher, Eaton says lightning arrestors or whole-building surge protection may add protection. That is engineering work: IEC 62305-4, listed on the Singapore Standards eShop, covers protecting electrical and electronic systems inside structures from lightning electromagnetic impulse. Ask your building management or a qualified electrical professional.

Standby, line-interactive or online UPS: which do you need?

Eaton's topology guide sets out the differences. A standby UPS runs equipment on mains and switches its inverter on only for an outage or severe sag, normally in about 10 ms or less; Eaton suits it to monitors, modems and routers, not workstations, servers, switches and storage. A line-interactive UPS also transfers in about 10 ms or less, but corrects low and high voltage without going to battery; Eaton calls it the most widely used design for loads under 10 kVA. An online double-conversion UPS runs the load from its inverter all the time, so there is zero transfer time, and it filters fast disturbances; Eaton positions it for sensitive equipment and poor power quality.

In the store, the APC Back-UPS Pro BR 900VA (BR900MI, S$452.50) is line-interactive with Automatic Voltage Regulation, rated 900 VA / 540 W, with a stepped-approximation output that suits most PCs, routers and switches. If the load has an active-PFC power supply, the Eaton 5SC 1000VA (5SC1000i, S$495.60) is line-interactive with a sine-wave output, 700 W, and USB and serial ports for Eaton Intelligent Power Protector shutdown. For a small server corner, the APC Easy UPS On-Line SRV 2000VA (SRV2KI-E, S$1,058.75) is double-conversion online, 1800 W, with a card slot for network management. Size on watts, not VA, using our UPS size calculator guide.

Lightning is the reminder. The real risk is the switch in the cupboard that nobody plugged into a UPS.

What should an office protect first?

Protect in order of what stops work when it goes down:

1. Internet and core network: fibre terminal, router or firewall, core switch and Wi-Fi. Without them, laptops on battery are still offline. A tidy, labelled cabinet makes this easier; see Your Network Cabinet Is a Mess. And That Could Cost You.
2. Storage and servers: NAS units and servers, with automatic shutdown so a long outage ends in a clean power-off rather than a crash.
3. Desktops with work in progress: finance, design and reception PCs. Laptops already have a battery.
4. Meeting rooms and phones: the display, video bar and the switch that powers them. We cover this in The Rain Didn't Kill Your Presentation. The Power Outage Did.
5. Everything else: printers, monitors and chargers usually need surge protection only.

One Eaton rule is worth repeating: a UPS already has built-in surge protection, and plugging a surge strip into one increases the risk of overload. Use strips at desks and UPS outlets directly for critical kit.

What should you check after a storm?

Check UPS displays for transfers to battery, confirm network equipment came back cleanly, and make sure batteries are healthy before the next storm; Your UPS Battery Might Be Dead Before You Realise It covers self-tests and replacement. For staff working from home on storm days, see Stuck at Home During a Thunderstorm? Your Next Meeting Is Still On., Singapore's Weather Is Unpredictable. Your Work Setup Shouldn't Be. and When MRT Disruptions Hit, Is Your Business Ready for Remote Work? On downtime planning, read Mitigating Power Outages and Downtime for Businesses with APC UPS.

Buying surge protection and UPS systems in Singapore

SourceIT supplies APC, Eaton and Targus with local warranty; the listings state 2 years for the APC Back-UPS Pro and Easy UPS models and the Targus strip, and 3 years on the UPS and internal battery for the Eaton 5SC per Eaton's Singapore price list. Prices are as listed on 24 Oct 2026, and all four items were in stock at the time of writing. A note on gaps: we do not currently list data-line (Ethernet or phone) surge protectors, so ask us if you need one sourced. Browse the APC UPS collection and the Eaton UPS collection. Send us your equipment list in watts and the runtime you want, and we will size it: use Request for Quotation on the product page, call (65) 6978 3502, email Sales@sourceit.com.sg or use our contact page.

Frequently asked questions

Does a UPS protect against lightning? A UPS has built-in surge protection for the equipment plugged into it, and it carries that equipment through dips and short outages. It is not a substitute for building-level lightning protection, which is designed by qualified engineers.

How many lightning days does Singapore have? MSS's 1991 to 2020 monthly means for Changi add up to about 175 lightning days a year, with the most in April, May and November.

Is a surge protector enough for my office PCs? It handles spikes but not dips or outages, so a desktop on a surge strip will still switch off in a power trip. Use a UPS for PCs that hold work in progress.

What is the difference between line-interactive and online UPS? A line-interactive UPS corrects voltage and transfers to battery in about 10 ms or less. An online double-conversion UPS runs the load from its inverter all the time, so there is no transfer time.

Can I plug a surge protector into a UPS? Eaton advises against it: UPS systems already have surge protection, and adding a strip increases the risk of overloading the UPS.