Douglas Krantz - Technical Writer - Describing How It Works

How do I Connect 24 Volt Horns and Strobes to a 12 Volt Panel?

Using existing 24 volt horns and strobes with a 12 volt fire alarm panel can be done. To do that, though, requires an added Notification Appliance Circuit Power Supply. Read the manuals on both the power supply an on the new fire alarm panel to make sure they're compatible.

I have a question about something

Greetings Douglas,

I have a Silent Knight 5104b panel with a few IDC's and about 8 Strobe Horn combos. Problem is the FACP is 12 Volt DC and the Horn/Strobes are 24 Volt DC.

Without swapping out all the Strobes with 12 volt strobes and have to get a lift or swapping out the 5104b with a panel that is 24 VDC, Can I connect a 24 Volt Power Booster to the 5104b and run the strobes from the power supply, Is there a relay on the 5104 that will work on a 24 volt power booster?

Thank you, M K

Silent Knight 5104B

The output you need on the Silent Knight 5104B is the Notification Appliance Circuit, sometimes simply called a NAC, but on the SK 5104B is called the Bell output. A bell is an Appliance that Notifies people (warns them of a fire).

There is a manual that comes with the SK 5104B that shows which terminals to use for the Bell, or NAC.

I Googled SK 5104B and got the manual at

Get the manual and read it. The specifications you are looking for are in the UL Requirements and in 3.11.2 Supervised Notification Appliance Wiring. There's also programming instructions in the installation book.

Silent Knight 5495

The Silent Knight 5495 Distributed Power Module is a booster power supply that can be used. Get the manual and read the UL Requirements to confirm. The manual also has the settings for the programming switches in the SK 5495.

I Googled SK 5495 and got the manual at

You should also talk to the technical support people with Silent Knight. Technical support is there to help people like you and me when we have problems.

Read the Manuals

I have 20 years experience troubleshooting fire alarm systems. That 20 years is part of 45 years of electronics work. I still read the manuals, you should too.

Douglas Krantz
Life Safety
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