Grounding Compression Connector Temperature Rating

[cuky2000]

Can a compression connector be sized as the grounding conductor rated for 1083 °C?
We are investigating the following:

1) Temperature Limit <1083 °C: It appears that the IEEE 142 and earlier version of the IEEE Std 80 revision 1986 (unconfirmer) has some reference how to derate the connector/cable combination. For example, compression connector withstand max. fusing temperature for 350 °C or 250°C depeding upon compliance with test standard. [highlight #FCE94F](if anyone has and old copy, please help to verify connector temperature rating).[/highlight]

2) Max. allow temperature of 1083 °C: The latest version of the IEEE Std 80 -2013 and the IEEE 837-2014, do not indicate specific temperature limit. It appears tha if the connector pass the fault test procedure, the connector/cable combination can be used per the cable rating [highlight #FCE94F](even at 1083°C for hard drawn copper).[/highlight]

Thanks for any though or clarification in this matter.

 

[7anoter4]

In my opinion, in the past for cadweld connections the maximum temperature recommended was 1083 [ copper fusing temperature] and for bolted connections 250oC.
Now IEEE 80/2013 recommends 250oC from mechanical resistance point of view.
BS 7430/2011 Table 5 Earth fault current densities for 1 s duration for earthing conductors with initial conductor temperature of 30 °C recommends:
Type of connection Maximum temperature [oC]
Welded 700
Brazed 450
Bolted 250
Soft soldered 150

 

[7anoter4]

By the way IEEE 837/2002 11.6 Fault-current test current:
The symmetrical rms fault current shall be 90% of the fusion current for the remaining cross-sectional area
of the control conductor calculated for a 10 s duration

 

[cuky2000]

Hello 7anter4,

Thanks for your post. It appears that in the pass version of the IEEE standard 80 there were limited temperature for different type of joint connectors. However, those limitations have been removed and simplified to a pass or fail a set of stringent tests of different sizes control tested conductor and connector combinations including material rated for 1083 oC.

It is confusing for engineers select and apply connector for ground grid application in substation design with pass and present practice still remaining in utilities specs. Below are a few key paragraphs quoted from latest standards:

IEEE Std 837-2014:[/b] the “Fault-current test Current” is 90% of the fusing current of the control conductor but for a duration of 10 second. This is established to prevent loss of the conductor and provide a method of measuring resistance reading after three repeated fault surges.]

Comment: for application with clearing time less than 1 second, the connector capability should easily withstand more than the 90% current test.

IEEE Std 80-2013:[/b] Grounding connection that pass IEEE Std 837 satisfy all the criteria-electrical conductivity, corrosion resistance, current carrying capacity, and mechanical strength.]

Comment: The IEEE Std 80-2014, do not have limited temperature for connector. Please refer the excerpt below indicating that the connector that pass the IEEE Std 837,are suitable for all grounding applications and require no special consideration, such as temperature de-rating