Instantaneous Override Current (ABB Tmax)

[bdfig]

Hi, does anyone know what the instantaneous override current of an ABB Tmax T4S circuit breaker with PR222 trip unit is? I cannot seem to find an ABB document which has this.

 

[ExanD]

override current??

 

[rhatcher]

The trip unit may not be equipped with instantaneous override. You should contact your ABB representative for confirmation.

 

[dpc]

I checked my EasyPower breaker library data. It does not show an instantaneous override being available for this breaker + trip unit. The maximum instantaneous setting is 12X.

 

[bdfig]

The reason I though it might have one is that in the ABB white paper "Working with the Trip Characteristic Curves of ABB SACE Low Voltage Circuit-Breakers" Figure 13 shows a TCC of the PR222DS/P-LSIG (with Tmax T4H250 CB) with I protection not activated. In the figure, the Instantaneous Override appears to cut into the short time curve at 3kA.

 

[dpc]

In the IEC world, it may well be different. The "identical" trip unit in the US can be configured differently from the equivalent IEC version due to differing codes and standards.

In my previous message I was referring to US equipment - I should have been more specific.

 

[EddyWirbelstrom]

The ABB trip unit PR222DS Instantaneous (I3) setting range is from 1.5 to 12 x In.
There is no OFF setting on the PR222DS Instantaneous element.
Some ACBs have an OFF setting on the Instantaneous element, however if the current approaches the breaker interrupt rating Icu or Ics, the Instantaneous element will automatically operate.

 

[bdfig]

ABB SACE Protection and Control Devices appears to show that the instantaneous setting can be turned off (I have attached the relevant page). Also Icu and Ics are much higher than the instantaneous override maximum setting.

 

[dpc]

Is this a UL or an IEC application? It can make a difference. Also, some new circuit breakers can be purchased as molded case circuit breakers or as low voltage power circuit breakers just by changing a part number. This will also impact the available options on the instantaneous settings.

If this is built to UL molded case circuit breaker standards, it will have an instantaneous trip (either by setting or override)

 

[bdfig]

It is an IEC Application.

 

[dpc]

Then you can probably ignore anything that those of us in the US have been telling you.