Relay Cutoff Switches 1

[jliu1]

I am working on a relay panel project. Customer asking for install relay alarm cutoff and relay trip cutoff switches. Used Flexitest FT-1 before. But here are the customer requirements:

It is requrested to two control switches in each relay panel.
1. Relay Alarm Cutoff: Disable any local relay alarms during testing (i.e. primary and/or backup relay or ground relay (if applicable))
2. Relay Trip Cutoff: Disable the trip function. Even though the flexitest switches can be used, a cutoff switch will be easier from a maintenance standpoint.

Not sure what switches can be used. Any suggestion appreacited.

 

[dpc]

You can use a standard heavy-duty oil-tigh selector switch or toggle switch.

But.....

Trip cutoff switch should be strongly discouraged. "Easier from a maintenance standpoint" is a big red flag. Running the trip through the test switch is one thing, but a readily accessible trip blocking switch seems like a bad idea. Supervisory cutout switches are pretty common.

 

[thermionic1]

We have a customer with similar requests.

The alarm cut outs are DPST knife switches, located in the back of the panel.

In our case the 50BF switches are 2 position rotary (electroswitch) mounted in the panel, much like a 86 LOR or 101 Switch. I believe this sw is also wired to SCADA for position indication.

There are also isolation available via the traditional FT switch.

I have also questioned the need or, rather, story behind this level of (in my opinion) unnecessary redundancy.