Power awareness for small sites: loads, UPS sizing checks and PDUs
For technicians who install or support equipment in comms closets and small server rooms and need to check whether there is enough power before plugging something in. No electrical background is needed; you should be comfortable with basic arithmetic. The course covers turning nameplate and measured readings into watts, VA and amps, checking a UPS's load against both its ratings, reading a manufacturer's runtime chart, choosing a rack PDU type and keeping A/B feeds able to fail over, and the limits on what a technician should touch. Safety references are US (OSHA); other countries have their own rules. The course does not qualify you to do electrical work and is not a licence: circuits, breakers and receptacles are for qualified electricians. For deeper UPS design and cooling, continue with Power, UPS and cooling for small server rooms.
- Level
- Beginner
- Length
- About 80 minutes
- Contents
- 5 lessons · final exam
- Status
- Published · updated 10 Oct 2026
Skills you'll practise
- Calculate a device's or rack's load in watts, VA and amps from nameplate or measured readings
- Calculate a UPS's load percentage against both its watt and VA ratings and identify an overload
- Estimate UPS runtime from a manufacturer's runtime chart and plan with the conservative figure
- Choose a rack PDU type and check that A/B feeds can each carry the full load if the other fails
- Identify which power tasks a technician may do and which belong to a qualified electrician
Course outline
- 1.Calculate load in watts, VA and ampsLesson · 16 min
- 2.Calculate a UPS's load percentage against both ratingsLesson · 16 min
- 3.Estimate UPS runtime from a manufacturer's runtime chartLesson · 14 min
- 4.Choose a PDU type and keep A/B feeds able to fail overLesson · 14 min
- 5.Know which power tasks are yours and which are an electrician'sLesson · 10 min
- 6.Power awareness for small sites: loads, UPS sizing checks and PDUs: knowledge checkKnowledge check · 13 questions
- 7.Power awareness for small sites: loads, UPS sizing checks and PDUs: practical exerciseKnowledge check · 1 question
- 8.Final exam10 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- Wikipedia: Volt-ampere (apparent power, power factor, UPS ratings in both VA and W)
- ENERGY STAR: Uninterruptible power supplies, buying guidance
- Vertiv: What is a rack PDU? (basic, metered, monitored and switched rack PDUs; C13 and C19 outlets)
- OSHA standard interpretation (18 November 2002): Compliance requirements for relocatable power taps or power strips
- OSHA 29 CFR 1910.303: Electric utilization systems, general requirements (listed equipment, marking, working space)
- OSHA: Electrical safety topic page
See it with your own jobs and topics
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