Termination temperatures around the globe

[T.M.Haja Sahib]

XPLE is becoming more common.
Two parallel 185mm² would do and if there are no abnormal ambients, then possibly even two 150 could handle it.

The XLPE cable may not be used at its full current carrying capacity as the cable conductor temperature becomes 90 degree centigrade, whereas the generator terminals, for example, may be rated for 60 degree centigrade only. Only when there are suitable derating factors per site conditions, does the application of XLPE cable become appropriate.

 

[Besoeker]

The XLPE cable may not be used at its full current carrying capacity as the cable conductor temperature becomes 90 degree centigrade, whereas the generator terminals, for example, may be rated for 60 degree centigrade only. Only when there are suitable derating factors per site conditions, does the application of XLPE cable become appropriate.

The 185mm² would be running significantly below its rating and I see no basis for your assumption that the genny terminals may be rated for 60C only. Where did you dredge that up from?

 

[T.M.Haja Sahib]

The 185mm² would be running significantly below its rating

This should be checked with tables whether the 'running current' brings the cable conductor temperature down to 60 degree.

I see no basis for your assumption that the genny terminals may be rated for 60C only.

Even if the genny terminals may be rated for more than 60 degree, the terminations of CB, switches etc., on the other end are usually rated for 60 degrees only.

 

[Besoeker]

Even if the genny terminals may be rated for more than 60 degree, the terminations of CB, switches etc., on the other end are usually rated for 60 degrees only.

On what do you base that?

 

[T.M.Haja Sahib]

On what do you base that?

NEC

 

[Besoeker]

NEC

I thought maybe so.
The generator is 400V 50Hz.

 

[T.M.Haja Sahib]

The generator is 400V 50Hz.

So...?

 

[Besoeker]

So...?

The nation referred to in the National Electrical Code is United States of America.

United States of America does not use 400V 50Hz.

 

[T.M.Haja Sahib]

The issue here relates to cable sizes,application temperatures etc.,which every nation uses.

 

[Besoeker]

The issue here relates to cable sizes,application temperatures etc.,which every nation uses.

Yes. So?

 

[T.M.Haja Sahib]

The terminals of switches, circuit breakers etc., in all nations are usually rated for 60C.

The full load operating temperature of XLPE cables manufactured in all nations is 90C.

Correct or not?

 

[Besoeker]

The terminals of switches, circuit breakers etc., in all nations are usually rated for 60C.

The full load operating temperature of XLPE cables manufactured in all nations is 90C.

So you are conversant with the regulations for all nations?
That is enormously or even incredibly impressive.
Regrettably, I don't have such an all-encompassing knowledge nor have the erudition to absorb such a wealth of diverse regulations, rules and practices. I'm a mere mortal with mortal constraints and mortal limitations. And, being so impoverished in my familiarity of all national regulations, I can't confirm that you are correct.

But I'm practically certain that you are not.

BS7671 cable tables list 70C thermoplastic (Table 4D1A, for example) and 90C thermosetting insulated cables.
So, ask yourself this simple question.
Why would anyone make such cables if they couldn't be used at their ratings?
Yet they do.

 

[K8MHZ]

So you are conversant with the regulations for all nations?
That is enormously or even incredibly impressive.
Regrettably, I don't have such an all-encompassing knowledge nor have the erudition to absorb such a wealth of diverse regulations, rules and practices. I'm a mere mortal with mortal constraints and mortal limitations. And, being so impoverished in my familiarity of all national regulations, I can't confirm that you are correct.

But I'm practically certain that you are not.

BS7671 cable tables list 70C thermoplastic (Table 4D1A, for example) and 90C thermosetting insulated cables.
So, ask yourself this simple question.
Why would anyone make such cables if they couldn't be used at their ratings?
Yet they do.

The 90 degree rating is used on 90 degree cable as a place to start our de-rating calculations. The final figure must be based upon the lowest temperature rating of the run, connectors and terminals included. Just as an example, a breaker may have a 60 degree terminal where main lug connection may have a 75 degree rating. Most wire nuts are rated at 105 degrees.

Also, luminaires require 90 degree cable to be connected to them, regardless of how much current it carries.

 

[Besoeker]

The 90 degree rating is used on 90 degree cable as a place to start our de-rating calculations. The final figure must be based upon the lowest temperature rating of the run, connectors and terminals included. Just as an example, a breaker may have a 60 degree terminal where main lug connection may have a 75 degree rating.

We don't have, or I've never seen, anything limited by terminal ratings. I've just looked at, for example, a load break switch and that has a maximum ambient but no, so far as I can determine, a specific temperature rating for its terminals.

And I haven't seen a wire nut used in probably four decades. Kit that may need to have a conductor like a switching wire looped there normally has terminals for that purpose.

 

[T.M.Haja Sahib]

We don't have, or I've never seen, anything limited by terminal ratings. I've just looked at, for example, a load break switch and that has a maximum ambient but no, so far as I can determine, a specific temperature rating for its terminals.

If you look further into the standard IEC or NEMA which the device i.e load break switch conforms to, you may come to know about the terminal temperature rating of it.

And I haven't seen a wire nut used in probably four decades. Kit that may need to have a conductor like a switching wire looped there normally has terminals for that purpose.

May be you would have understood better if instead of wirenut, terminal block was mentioned?

 

[T.M.Haja Sahib]

So you are conversant with the regulations for all nations?
That is enormously or even incredibly impressive.
Regrettably, I don't have such an all-encompassing knowledge nor have the erudition to absorb such a wealth of diverse regulations, rules and practices. I'm a mere mortal with mortal constraints and mortal limitations. And, being so impoverished in my familiarity of all national regulations, I can't confirm that you are correct.

You need not undertake such a tremendous project, IMO. Only there are two standards NEMA and IEC. By studying the two, a fair idea can be obtained for the purpose at hand.

 

[Besoeker]

If you look further into the standard IEC or NEMA which the device i.e load break switch conforms to, you may come to know about the terminal temperature rating of it.

I did look at the detailed specifications for the device I mentioned.
And, once again, let me remind you that the nation referred to in National Electrical Manufacturers Association is United States of America.
United States of America does not use 400V 50Hz.

May be you would have understood better if instead of wirenut, terminal block was mentioned?

I understand perfectly well what a wire nut is.
It seems that you don't.

 

[T.M.Haja Sahib]

I did look at the detailed specifications for the device I mentioned.

Then go ahead and read further into the standard to which the device conforms.

And, once again, let me remind you that the nation referred to in National Electrical Manufacturers Association is United States of America.
United States of America does not use 400V 50Hz.

But the other standard I mentioned does. I want to bring to your kind attention there are some common features between the two standards with regard to terminal temperature rating.

 

[Besoeker]

I want to bring to your kind attention there are some common features between the two standards with regard to terminal temperature rating.

Care to cite them?

 

[Besoeker]

Then go ahead and read further into the standard to which the device conforms.

Just for you......
Table 2 clause 7.2.2.1 of IEC 60947-1 details the permissible temperature rise based on the type of metal used in the construction of the terminals.
For example, where the terminals are made of silver plated or nickel plated copper or brass, the maximum rise above ambient is 70 K, resulting in a maximum termination temperature of 110C.

K is for Kelvin.

Will you now give me your kind consent to employ XPLE at it's full rating for this particular device?
Pretty please?