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What is the difference between modular and N+1 UPS Systems?

Published by Lee Kelly on 09 March 2020

In the UPS world, there are a few different types of UPS systems that can be installed to protect your electrical equipment or buildings. With pricing ranging and install times varying the option you choose needs to be the correct choice for your budget and your backup needs. We are going to be exploring the difference between two types of system in this article, and that is the difference between modular and N+1 UPS systems.

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Modular UPS, what is it?

A modular UPS system is a UPS that can be configured and key parts changed while on-site because it has a modular design technology. With a range of different options, you can configure a system for your current power draw and then quickly add power modules to increase the capacity or redundancy of the UPS. There are a few different manufactures of modular UPS, and you can see our top 5 modular UPS systems.

N+1 UPS system, what is it?

An N+1 UPS system uses multiple UPS to provide redundancy and extra capacity. These styles of systems can take up a large footprint. The N+1 system is designed so that a UPS can be taken entirely offline and still provide you backup with the remaining UPS, however, while working on only one UPS you have no redundancy. This allows for maintenance or a swap out to take place.

What’s the difference?

There are a few differences between modular and N+1 UPS systems. These range from cost to size and efficiency, to the electrical infrastructure required to enable the systems to work.

In a typical UPS N+1 system, you may have two or more UPS in parallel to increase the redundancy or capacity of the system. For extra capacity or redundancy, you would have to add another UPS into this system, making the system N+1, N+2, N+3. As opposed to a modular UPS system where you can start with an 80kVA frame and install power modules until you hit the capacity of that frame and once you hit that capacity you need to install another frame if the electrical infrastructure allows for this. This setup usually means that a modular UPS has a smaller footprint meaning it can be ideal for buildings that have minimal space.

The cost for a modular UPS can be relatively reasonable if you are looking for a redundant solution. This is since you can size the UPS for your current demand and then expand when required as your company grows and as budget allows. This helps reduce the initial costs for a redundant solution while allowing for expandability. As opposed to an N+1 UPS, which usually has to be sized for a future capacity rather than the current capacity meaning you could have a current capacity of 30kVA. However, your UPS system can have a future capacity of 100kVA. That is an extra cost and could potentially even be oversized, and you never use the system at full capacity. An additional factor is that typically at lower UPS load, they are less efficient compared to running at an 80 - 95% load. Finally, it is worth remembering in an N+1  configuration should the solution use a centralised battery or a battery per UPS Chassis.

How can we help?

Critical Power Supplies offers a wide range of solutions from power planning and design, data centre design, factory witness testing, maintenance and monitoring and much more find out about all our offerings here.

If you are interested in a modular or a redundant UPS solution, you can contact our dedicated sales and support team on 0800 978 8988, or you can submit your tender or ask for help via our email here.