The Honeywell 7945 is a surface mount magnetic contact with leads instead of terminals. The 7945 is also a member of Honeywell’s XTP Series of commercial contacts. All XTP contacts are designed to protect against lightning strikes and power surges. As commercial contacts are often installed in outdoor buildings, power surges can be a major problem. If enough voltage runs through a contact, the internal reed switch becomes fused and the contact will never go into alarm regardless of whether the magnet is adjacent or not. Unfortunately, there is no way to supervise a fused contact. Unless you are regularly testing all of your commercial contacts, your property may not be protected if you are using a non-XTP commercial contact and it is installed outside. Use Honeywell XTP contacts so you don't have to worry about a surge fusing your contacts as they can withstand a power surge of up to 2400VDC.
The Honeywell 7945 comes in (3) colors. If you want a white contact , you should order the 7945WH. If you want brown, you should order the 7945BR. Finally, if you want a grey contact, you should order the 7945GY.
Unlike most Honeywell contacts that use terminal screws for wiring connections, the 7945 contact has a 6’ CLII cable lead with (2) wires which you would use to wire to your zone circuit. The internal reed switch for the 7945 is a Form A, SPST, normally closed contact. If you wanted a Form C, SPDT, normally closed or normally open contact, you should look at the 7945-2GY contact instead. The normally closed contact for the Honeywell 7945 is rated for 100mA at 28VDC.
The 7945 XTP surface mount magnetic contact has many of the features found in Honeywell commercial contacts. In addition to the XTP surge protection, the 7845 commercial contact has an epoxy sealed case to protect it from water or corrosion. Also, the Honeywell 7945 operates in temperatures between -40° F and 194° F. Finally, the contact has an extra wide magnet gap of 2.5” which makes it ideal for the more unique commercial applications. If your magnet gap is smaller than 1”, any door or opening you are trying to protect that may shift in the wind will cause false alarms. With the 7945 contact’s wide gap, you can be confident that all alarms triggered are real emergency events.
There are (3) different replacement magnets for the 7945 commercial contact depending on which color you choose. If you choose the white 7945WH contact, you should use the 7945WH-M magnet if you need a replacement. The 7945BR-M is a brown magnet to match the 7945BR contact and the 7945GY-M is a grey magnet to match both the 7945GY contact and the 7945-2GY contact.