StuartO's Activities

Connect Calculation Issue

StuartO — Fri, 17 Jun 2022 12:25:50 GMT

Hi,

Sizing cables as per BS7676.

It (tabulated cable rating)

In (protective device rating)

It > In/de-rating factors.

Therefore 70mm2 SW/PVC 4 C = 207A table 4D4A

In = 200A cg = 0.87

200A/0.87 = 229A

207>229 It is not greater than In therefore cable is not big enough for a 200A fuse, however the calculation has not flagged this as an error.

Please advise.

Fail type 5

StuartO — Wed, 18 May 2022 13:29:47 GMT

Please advise what causes a fail type 5.

Fail Type 7

Paul Trenter — Wed, 22 Dec 2021 10:30:28 GMT

Connect Fail Type 7

I noticed a question back in 2019 with regard to fail type 7 as below.

Under the fail help, fail type 7 is determined as "Fails as no I2t data is available for the devices, assume a failure by default".

I assume that the I2t data for the specific devices is not present in the data file for that particular device, in this instance Schneider Mirologic ACB's.

With no I2t data the calculation defaults to unlimited energy let through, which then fails the k2s2 > I2t test.

As such I'm left with a failure on the main supply where I'm using Schenider ACB's on both the LV supply (in this case an outgoing transformer) and on the incoming side of the main panel board.

Using the generic ACB on the LV feeder overcomes the issues, but then gives me a discrimination problem with the down stream Schneider ACB.

Why is the I2t data not included in the calculation? And how do I overcome the issues?

Schneider ACB's must be one of the most commonly used protective devices of this type.

I too have the need to produce calculations for scrutiny by a Consultant.

When will this issue be resolved? Using a Generic ACB does not satisfy the Consultant, they require the verified calculations using the devices we will be installing.

Please advise when a fix will be provided.

Connect calculation error

StuartO — Mon, 11 Oct 2021 14:09:56 GMT

I have noticed that running a calculation, Connect takes account of the of the circuit current and not the fuse size as per your calculation help.

BS7671

It> In (divided by the grouping factors)

My circuit is protected by a 100A MCCB and has an 80A load.

It = 2-C SWA 4D4A ref E 128A.

The grouping factor of the SWA 2C cable is 0.78. 100A/0.78 = 128.2A grater than It, therefore the cable is under sized.

When the load is fixed at 80A the circuit passes, when fixed at 100A the circuit fails. In both instance the circuit should fail.

The calculation seems to take no account of the protective device size, and sizes the cable on the load only. Meaning that under normal operation should the 80A load increase to the protective device size of 100A the cable is not rated to take the load.

Regards

Stuart

Fault Level at distribution board close to transformer

Ian S Langley — Thu, 28 Jan 2021 17:14:49 GMT

Ive just run a calculation for a distribution board with the following inputs

1000KVA transformer @ 4.75% showing a fault current as 28.7KA EFLI at 0.0089.

On this transformer there is a bolt on protection

125A Supply is via a 125A 3P fixed pattern ABB TMax MCCB type XT1N160R125 fitted with TMA thermal magnetic overcurrent protection, providing adjustable overcurrent (0.7 – 1 x In) and short circuit protection. (set at 0.8) = 100A

The cable from this cable is to be a 25mm 4 core run on tray on it own for 5m before it terminates in a Distribution board.

My problem is at the Main Panel the fault level is 28.7KA (from supply page), But my calc (short circuit fault summary) at the DB (only 5m away is coming out as 7,233A (b). I would expect it to be in the 20's range.

Am i missing something

I was expecting a fault level issue due to the proximity of the board to the supply?

regards

Ian S Langley

Maximum Zs values.

Ian Griffiths — Tue, 13 Jun 2017 09:51:38 GMT

We have undertaken circuit calculations that utilise Eaton MEM (MEMShield 3) devices. The calculation completes successfully and indicates the Zs values pass.
We note that regulation 411.4.7 allows the calculation of Zs to satisfy the disconnection requirement and that this is the Hevacomp calculation method.
The circuits have subsequently been tested on site by the contractor and have been noted that the values exceed those deemed to comply within BS7671 Table 41.3
We have provided the calculated values as reassurance however the contractor (to satisfy himself) has referred the issue to the NICEIC.
The NICEIC response is as follows:
“For the circuits that are not RCD protected if Eaton are able to confirm that their devices have a higher allowed Zs value and they still trip within the required time, thus making the currently failed circuits compliant, their max Zs values can be inputted to the test sheets instead of the ones from BS7671 and should result in the circuit passing.”
We have requested published value of Zs from Eaton, which they have provided – but these are the same values as listed in BS7671.
The question therefore is where have you sourced your Eaton Zs values? If we can receive this it will give the required credibility to the calculation results to be used within the completion certificate.
Regards,

SWA Armour size for CPC

StuartO — Tue, 18 Feb 2020 11:06:13 GMT

Please advise.

Below is an extract from the Heva cable data base for 4-C XLPE/SWA (LSF) cable.

And below extract from Prysmian data sheet for the same cable.

As can been seen the Heva data utilises a larger CSA of armour, which would give rise to move favourable conditions due to the higher quantity of earth conductor.

Can you please clarify the data used for the SWA armour used in multi core SWA cables for CPC, and advise the implications of the larger CSA of armour.

70 degC cable operating temperature

Richard Foster — Fri, 24 May 2019 07:40:06 GMT

Hi,

Is there a way in Hevacomp Connect to limit the operating temperature of a 90degC cable to 70 degC?

Or is the only solution to substitute for a cable that has a maximum operating temperature of 70 degC from one that can run to 90 degC

I think this problem has been raised before but a year or two ago,

Many thanks

Richard

Ask A Question II

Tue, 18 Feb 2020 03:22:20 GMT

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Can't change server path

StuartO — Thu, 16 Jan 2020 14:03:11 GMT

We have a new machine in the office, installed all the required parts, services packs etc. When I come to set the location for the main project path for windows path file onto our server I get the following error message and I'm unable to change the server path.

The user was already listed in the path of users but I now can't change the path.

Please advise.

Help with installation connect

StuartO — Fri, 01 Nov 2019 11:25:13 GMT

Due to the custom cable file becoming corrupted on one of our machines, we had an error 53 which we could not resolve despite following all the instructions on moving custom cable files.

As such we have carried out a fresh install, and removed all previous heva data files from C: program data.

We have download the latest update and it's dependencies to ensure we have the most up to date software.

After install we still have the error 53, and the heva data in program data only includes mech items, the IEE folder is not installed.

Please advise.

Connect Fail Type 7

StuartO — Tue, 13 Aug 2019 11:54:32 GMT

Under the fail help, fail type 7 is determined as "Fails as no I2t data is available for the devices, assume a failure by default".

I assume that the I2t data for the specific devices is not present in the data file for that particular device, in this instance Schneider Mirologic ACB's.

With no I2t data the calculation defaults to unlimited energy let through, which then fails the k2s2 > I2t test.

As such I'm left with a failure on the main supply where I'm using Schenider ACB's on both the LV supply (in this case an outgoing transformer) and on the incoming side of the main panel board.

Using the generic ACB on the LV feeder overcomes the issues, but then gives me a discrimination problem with the down stream Schneider ACB.

Why is the I2t data not included in the calculation? And how do I overcome the issues?

Discussion Starter I

Thu, 08 Aug 2019 09:26:03 GMT

Start a discussion in a forum that receives 5 replies.

Cannot download update 26.06.00.12

StuartO — Thu, 08 Aug 2019 08:05:18 GMT

Using the update page https://communities.bentley.com/products/building/performance/w/building_performance__wiki/23368/download-and-install-the-hevacomp-latest-update

The software downloads link takes me to a blank page.

Please advise how I can download the latest update.

Eaton IZM ACB's

StuartO — Tue, 23 May 2017 08:42:12 GMT

We have an incoming 2500A ACB device on a project as an Eaton IZMX40.

I cannot see this range listed in the drop down under Eaton products, and the generic Eaton ACB's do not offer the full range of adjustable settings required to clear discrimination faults.

I have tried to down load the Eaton data pack but this only adds the NZM range of MCCB's, which I already have installed.

Can you please assist.