atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring 66 block bridge clip fuses

Can anyone tell me what the bridge clip fuses are called? The ones I have used in the pasted are plastic normally clear and fuse one pair at a time. I usally just told the company I used to work for to get me more sneak fuses. Having a hard time finding some.

Thanks!

Matt

your probably thinking of sneak protectors , they used to be clear

Ive never seen those Sieman's ones Waine they're not used around these parts

Interesting. So have you ever had a customer that was just continuely getting hit by lighting and the secondary protection doesn't always stop the hit.
Could a sneak protector help this situation?

skip555 - I thought (I might have been told wrong)the ITW's were considered secondary protection. Are they not secondary protection?

Not really, 6string. Sneak current fuses are designed to protect trunk ports from abnormally high levels of loop current. Lightning would blast right on through a sneak fuse even if it blew open. If it travels five miles through open air, I can assure you that the 1/8" gap left by a blown sneak fuse isn't going to stop it. These are more of a "melt" fuse than a "blow" fuse, if that makes any sense.

Your solution is to provide adequate primary and secondary protection with a decent amount of inside cable between these devices. Putting them side-by-side really does nothing.

Anything that simply plugs onto a block is considered secondary protection. Not to mention that these devices can easily be bypassed in a pinch with standard briding clips. They can never be trusted as the sole means of protection for this reason alone.

Those Siemon units are quite common and readily available. Getting the replacement fuses to fit them might be another story.

Na I gave up on the fuse changing thing. It's more trouble than they are worth.

Ed is correct on all fronts here. Those sneak protectors have a specific "melt point" and are really designed to give way. But only when the current requirements are exceeded for too long.

Skip: Those thing are everywhere here, I cant seem to get rid of them. They are keyset savers and trust me when it comes to a new set or a CMP I would rather replace the CMP.

CPM-2PLUS is exactly what I was talking about. Thanks for the part number. We have provider here that sometimes the protection with the ground bars will effect the ringing on the lines. You will get like half ring when the protection is on causing fax machines not to pick up. I know these little fused clips work great on these type of lines though.

Thanks again!

Ed - Thanks for clearing that up for me.

I can personally attest to everything that has been said here. My firehouse just got whacked by lightning yesterday. I had three of those sneak fuses on the three incoming POTS lines. All of them got vaporized. The PBX is toast. I have some spare cards but I have a feeling its beyond swapping some cards out (Panasonic DBS). An ADSL modem, a router, and a LAN switch are all fried. I don't know how, but the dialer on the fire alarm survived even though it is ahead of the PBX.

The radio equipment had northern technologies lightning arrestors on the 66 blocks (clamps high voltage to a ground bus bar). They all martyred themselves but worked as intented. All our radio equipment was saved but the MFT's in the CO down the road got roasted.

I have to say these NT arrestors outperformed the traditional polyphasors we usued to use. The shop replaced the RTPA radio circuit polyphasors with the NT's this year and it was worth the added expense. They poly's are only $25 a piece and the NT's about 2-3 times more. But they worked where the polyphasors let me down. Lots more are on order now to protect the other circuits.