Fire Alarm Earth Faults Explained
A practical look at fire alarm earth faults, including what they are, what commonly causes them, why they can be so difficult to locate, and the strange problems they can create on an addressable loop.
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Practical tools and guidance for fire & security engineers
Free engineering calculators, structured technical guidance and field-focused articles for fire alarms, CCTV, networking, PoE, cabling and life safety systems.
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UK focused
Built for engineers
From the Fire Secure UK blog
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Practical guidance, engineering notes and project updates.
How RS-485 Actually Works: A Practical Engineer's Guide
A practical look at how RS-485 actually works, from differential signalling and twisted pairs to termination, biasing, bus topology and common-mode voltage. Written for engineers who use RS-485 in the field and want to understand what is really happening on the A and B...
See moreFire Alarm Zoning Is About Finding Fires
Fire alarm zones are meant to help people quickly locate a fire, not to make a panel configuration look neat. This article looks at how overcomplicated zoning, poor device descriptions and programming-led design can make systems harder to use, and why geographical clarity should...
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Popular engineering tools
Quick checks for common design, commissioning and maintenance tasks.
01
Fire alarm batteryStandby capacity, alarm load and derating
02
CCTV storageRetention, bitrate and usable capacity
03
PoE power budgetSwitch load, port limits and spare capacity
04
PoE UPS batteryBackup runtime and battery-bank sizing
05
Voltage dropCable resistance and percentage drop
06
DIP switch addressingBinary, Apollo and Hochiki presets
Structured technical reference
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Clear, connected guidance for systems encountered across the fire and security industry.
Fire alarms
System categories, cause and effect, interfaces and equipment guidance.
Cabling
Containment, support systems, cable types and installation rules.
Networking & PoE
Switches, VLANs, structured cabling, wireless links and power delivery.
Security systems
CCTV, access control and wider electronic security topics.
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About the platform
Frequently asked questions
What is Fire Secure UK?
A practical engineering resource for UK fire, security, CCTV, networking and life safety systems.
Who is it for?
Engineers, designers, commissioning engineers, technicians and others working with life safety systems.
Are the resources free?
Yes. The engineering tools, technical wiki and articles are currently free to use.
Do the calculators replace design verification?
No. Always check critical results against applicable standards, project requirements, manufacturer documentation and site measurements.