120kVA UPS in Kenya: Price, Full Load Current, Batteries and Generator Size

A 120kVA UPS in Kenya carries up to 120 kW of critical load, enough for a mid-sized data centre, a hospital or a factory’s control systems. At Encom, the two 120kVA choices are the SIEL Safepower S 120K and the SIEL Safepower Evo HF 120K. Both are three-phase online double conversion units, and we quote each one per project because the battery bank sets most of the price.

Prices and specs checked on 29 October 2026.

Key takeaways

• Both SIEL 120kVA models deliver the full 120 kW, because their output power factor is 1.
• At full load, a 120kVA UPS draws about 173 A per phase on a 400 V three-phase supply.
• The Safepower S 120K weighs 155 kg, while the Evo HF 120K weighs 198 kg, according to SIEL.
• A generator for a 120kVA UPS usually falls between 150 and 240 kVA, using the common 1.25 to 2 times rule.
• Kenyan electricity users averaged 8.39 hours of blackouts a month, according to EPRA data.

What is the 120kVA UPS price in Kenya?

There is no fixed shelf price for a 120kVA UPS in Kenya, because the battery bank changes the total so much. For example, 10 minutes of backup at 120 kW needs a far smaller bank than one hour. So we quote each SIEL unit once we know your load, your runtime and your site. Also, all Encom prices exclude VAT.

In particular, five things move the final figure:

• The model. Safepower S or Safepower Evo HF, since the Evo HF scales to more units in parallel.
• The battery bank. Standard VRLA blocks, or lithium (LiFePO4) when you choose the Evo HF.
• Battery cabinets. Neither 120K model holds batteries inside, so the bank always sits in separate cabinets.
• Redundancy. One unit, or two in parallel as N+1 when downtime is not an option.
• Installation. Cabling, breakers and a maintenance bypass switch.

What can a 120kVA UPS run?

A SIEL 120kVA UPS can carry up to 120 kW of running load, since kVA and kW are equal on both models. For instance, that covers a server hall, a full hospital with theatres and ICU, or the controls and IT of a large plant in Athi River or Thika.

For scale, average server racks still draw below 8 kW, according to the Uptime Institute’s 2024 survey. However, we advise running a UPS at no more than about 80% of its rating. That gives a planned load of about 96 kW, or roughly 12 average racks, with room left for growth and start-up surges.

Power is also the main reason sites go down. In fact, the Uptime Institute’s 2025 outage report states that “power remains the leading cause of impactful outages.”

What is the full load current of a 120kVA UPS?

At 400 V three-phase, a 120kVA UPS draws about 173 A per phase at full output. The formula is I = kVA × 1000 / (√3 × V), so 120,000 / (1.732 × 400) gives 173.2 A.

Because both units draw input at a power factor of 0.99, the input current stays close to these figures. Still, people often ask for a 120kVA UPS cable size, and we never give one blind. Cable size depends on run length, grouping and how the cable sits, so a licensed electrician must work it out. In Kenya, that work falls under EPRA’s electrical installation rules.

Safepower S 120K vs Evo HF 120K: which SIEL fits?

Both models are VFI-SS-111 under IEC EN 62040-3, the top class for online UPS systems. The real choice comes down to batteries, growth and the room you have.

When to choose the Safepower S 120K

Pick the SIEL Safepower S 120K when you want the higher online efficiency and a shorter cabinet. At 1,100 mm tall, it fits rooms with low ceilings or tight doorways. It also has a 40 A charger, a diesel mode input for generator sites, remote emergency power off and a wide 208 to 478 V input range.

When to choose the Evo HF 120K

Pick the SIEL Safepower Evo HF 120K when you plan to grow or want lithium batteries. Up to eight units can run in parallel, so a data centre can add capacity later. It also runs at 103% load with no time limit. SIEL describes the range as “ideal for the protection of computer networks, telecommunications and critical systems in general.”

How many batteries does a 120kVA UPS need?

A SIEL 120kVA UPS uses one or more strings of 12 V blocks, split around a centre point. The Evo HF 120K takes 40 blocks per string (20 + 20). For more runtime, we then add further strings in external cabinets.

Meanwhile, the Safepower S 120K takes an adjustable string of 30 to 50 blocks. However, the count matters a lot. According to SIEL, 36 to 50 blocks give full power. In contrast, 32 or 34 blocks cut the output power factor to 0.9, or about 108 kW. Likewise, 30 blocks cut it to 0.8, or about 96 kW. That is why we never trim blocks to save money on a 120kVA quote.

How long will a 120kVA UPS run on battery?

Runtime depends on your load and your battery bank, so there is no single answer. For example, 15 minutes at 120 kW means the batteries must deliver 30 kWh, plus losses. At half load, the same bank runs much longer.

Your target also depends on whether you have a generator. According to a Vertiv paper for the Battcon conference, UPS batteries have traditionally been sized for 15 minutes, since the UPS only bridges the gap until a generator takes over. As a result, we size from the maker’s discharge tables rather than simple division.

• With a generator: 10 to 15 minutes is usually enough, because the generator carries the long outage.
• Without a generator: plan for your longest likely outage instead. Kenyans face about 8.39 hours of blackouts a month, according to EPRA data reported by People Daily.
• Planned outages: Kenya Power posts its maintenance notices on its official X account, so check how long they last in your area.

What size generator suits a 120kVA UPS?

Plan for a generator of about 150 to 240 kVA when it only feeds the UPS. UK specialist UPS Systems advises sizing a generator at 1.25 to 2 times the UPS output, because a UPS can draw a distorted current that heats the alternator. If the generator also runs air conditioning or lighting, size it for that total load instead.

That distortion is the real issue. Consulting-Specifying Engineer warns that “harmonic distortion can cause excessive heating at the generator”, and it notes that a 6-pulse rectifier typically has about 30% THD. By comparison, both SIEL 120K models keep input distortion (THDi) at 3% or less. So they sit at the gentle end, and your generator may not need the top of the ratio. In any case, your electrician should confirm the final size.

How heavy is a 120kVA UPS, and where should it go?

The Safepower S 120K weighs 155 kg and the Evo HF 120K weighs 198 kg, without batteries. So both need a pallet jack, a clear route and a doorway wide enough for the cabinet. The Evo HF stands 1,600 mm tall, while the Safepower S stands 1,100 mm.

Heat matters too. At full load and 96.5% efficiency, a 120kVA UPS loses about 4.4 kW as heat. In ECO mode at 99%, that falls to about 1.2 kW. Because of this, plan cooling for the UPS room as well as the server room. SIEL rates both models for 0 to 40 °C and up to 95% humidity without condensation. Since the cabinets are IP20, keep them indoors and away from dust.

One 120kVA UPS or two smaller units?

For most sites that cannot stop, two units in parallel beat one big unit. For example, two 120K units as N+1 can carry a 120 kW load even while one is down for service. Our data centre UPS guide on redundancy and batteries explains the options in more detail.

On the other hand, if your load is heading past 120 kW, look at the Safepower S 150K or the Evo HF 160K. If it is smaller, the Evo HF 100K or our 60kVA SIEL guide may suit you better. For phase balancing and per phase loads, also read how to size a three phase UPS for your site.

How to get a 120kVA UPS quote in Kenya

To quote quickly, we need your load in kW or an equipment list, your supply voltage, your runtime and whether you have a generator. Then we come back with the right model and battery setup. Encom Digital is the only retailer of SIEL in Kenya and East Africa, and we supply each unit on order. Request a quote on WhatsApp on +254 714 962 072, or Email us.

Finally, compare every range in our SIEL UPS buyer’s guide, or browse the critical and industrial UPS range.

Frequently asked questions

120kVA UPS price and buying

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Batteries, generators and backup time