Three phase DB, water, you can geuss!

[J25GTi]

Well, having just joined up i thought id post some of the work i get involved with and what not and generally introduce myself!

Im Jamie, I'm 22, and an industrial/commercial electrician in the southwest.

Generally i get alot of fault finding and reactive installation work to do, and I'm just in the process of going self employed now.

But anyway, i went to a site the other day to carry out a EICR and this is what was awaiting me! A 50a TP-N DB that was mounted next to a garage door and was been leaked on by the roof!

As you can see its a bit of a mess!

Well, it turns out that <3 months ago a large electrical contractor in the area had fitted a new supply to the forklift charger (50a single phase), but didnt have any cable big enough so they doubled up 2x 6mm cables for L,N,E, *rolls eyes*

It also turns out the MCB was upside down, causing mass confusion to the guys on site as it kept tripping out due to only been a "b" type

Earth didnt quite fit in the terminal it seems -

So I isolated the board and made safe and the client agreed to let us install a new fuseboard and sort out the cabling issues!

Found a burnt out lighting circuit then realised this might have something to do with it -

So on with a new DB and enclosure,

I elected for a GRP IP65 enclosure with an eaton TP-N DB inside with all cables + conduits passed through the GRP enclosure with stuffing glands and suitable washers with weather proof glands going into the DB.

New supply for the forklift charger -

Lighting Circuit renewed -

There we have it,

Hopefully they are all up to your exacting standards, and C+C is welcome!

Jamie

 

[Top Cat]

Welcome (pictures don't work!)

 

[J25GTi]

Do they not? I can see them fine? :/

 

[GLENNSPARK]

well i aint in the industrial sector (as yet)...but your heart sinks when you see stuff like the earthing and back to front MCBs....protius n all wherever you find it.....

 

[GLENNSPARK]

Welcome (pictures don't work!)

maybe it was a case of "curiosity killed he cat".......

 

[GLENNSPARK]

welcome to`t forum by the way.....

 

[J25GTi]

maybe it was a case of "curiosity killed he cat".......

So they do work? Confused.com!

Yeah, I just dont get how people see that it is okay to do stuff like this! It beggars belief

 

[telectrix]

Welcome (pictures don't work!)

take the lid off your dustbin. they work for me

 

[Welchyboy]

Nice work!

 

[trev]

Welcome aboard me hearty yyeeaaaarrrgggghhhhh
Twas a thing of beauty before but prettier still after

 

[Tricksy]

At least they managed to get the core colours to match the coloured dots on the original board. :smilewinkgrin:

 

[sedgy34]

:welcome:

 

[Tricksy]

Forgot to say welcome. I'm new here too. Hope you guys are friendly.

 

[Engineer54]

Welcome to the forum....

By the way, there's nothing wrong with parallel supplies, so no need to roll your eyes to far...lol!!!
For a 50A supply requirement they could of used 2 X 4mm, easier to pull and all!! lol!!

 

[J25GTi]

Welcome to the forum....

By the way, there's nothing wrong with parallel supplies, so no need to roll your eyes to far...lol!!!
For a 50A supply requirement they could of used 2 X 4mm, easier to pull and all!! lol!!

Now explain to me why there is nothing wrong with it? I dont quite see it?

If you have 2x cables capable of 30a each, running a 50 a load, and one leg fails, you end up with one cable running 50a thats only rated to 30a?

 

[Engineer54]

Now explain to me why there is nothing wrong with it? I dont quite see it?

If you have 2x cables capable of 30a each, running a 50 a load, and one leg fails, you end up with one cable running 50a thats only rated to 30a?

I think you would have to explain to me why would one leg fail?? Running ''Parallel'' supplies is standard practice, it can increase current carrying abilities, reduce volt drop, reduce labour costs and in many circumstances, reduce the overall cost of the installation over using a far larger sized single cable!!

Most of the supplies feeding our main switch boards and most sub switchboards on this and every other project i've ever worked on, will use parallel supplies, and i'm not talking of just 2 parallel cables but several per phase & N etc!!! Your talking about a couple of cables supplying 50A, and i'm talking of several cables supplying 3500A!!! Now think about the size of a single cable supplying that sort of load, ...doesn't bare thinking about does it?? ...lol!!!!

Standard Practice as i stated before!!!

 

[J25GTi]

I think you would have to explain to me why would one leg fail?? Running ''Parallel'' supplies is standard practice, it can increase current carrying abilities, reduce volt drop, reduce labour costs and in many circumstances, reduce the overall cost of the installation over using a far larger sized single cable!!

Most of the supplies feeding our main switch boards and most sub switchboards on this and every other project i've ever worked on, will use parallel supplies, and i'm not talking of just 2 parallel cables but several per phase & N etc!!! Your talking about a couple of cables supplying 50A, and i'm talking of several cables supplying 3500A!!! Now think about the size of a single cable supplying that sort of load, ...doesn't bare thinking about does it?? ...lol!!!!

Standard Practice as i stated before!!!

Well having never seen it done before I wouldn't know! Seems a bit odd that you can do it. Because I was always taught not to ask why would a leg fail, but to ask what happens when it does fail?

Surely a an mcb etc has to be rated to the lowest conductor carrying capacity. Of which this conductor would be 30amps?

 

[Smudge]

I think you would have to explain to me why would one leg fail?? Running ''Parallel'' supplies is standard practice, it can increase current carrying abilities, reduce volt drop, reduce labour costs and in many circumstances, reduce the overall cost of the installation over using a far larger sized single cable!!

Most of the supplies feeding our main switch boards and most sub switchboards on this and every other project i've ever worked on, will use parallel supplies, and i'm not talking of just 2 parallel cables but several per phase & N etc!!! Your talking about a couple of cables supplying 50A, and i'm talking of several cables supplying 3500A!!! Now think about the size of a single cable supplying that sort of load, ...doesn't bare thinking about does it?? ...lol!!!!

Standard Practice as i stated before!!!

common practice at my place of work to run parallel supplies, easier when working with larger swa's etc. Welcome by the way, neat install too.

 

[spark 68]

I have to agree with E54 on this, it is industry standard practice to use parallel feeds, especially with the larger cables sizes for the reasons he has given, ie. practicality and costs.

 

[Engineer54]

Well having never seen it done before I wouldn't know! Seems a bit odd that you can do it. Because I was always taught not to ask why would a leg fail, but to ask what happens when it does fail?

Surely a an mcb etc has to be rated to the lowest conductor carrying capacity. Of which this conductor would be 30amps?

That, would frankly defeat the point wouldn't it?? Most main switchboards, will actually be constructed to accommodate parallel feeds and in some circumstances even outgoing ways...

Not sure why you are obsessed with one leg failing, why would just one leg fail? Taking that all connections have been professionally made off, what would you say, is the chances of that ever happening??

 

[Engineer54]

It should be pointed out that there ARE certain rules that govern the use of parallel supplies/feeds. The cables Must be of the same construction, Must be of the same CSA size, Must be substantially the same length point to point, should follow the same route in/by the same containment means.

Remember, we are not talking about a ring circuit, although a ring can be classed as a crude parallel circuit but one that serves multiple loads/points. However a true parallel circuit will supply/feed just one load point!!

 

[J25GTi]

That, would frankly defeat the point wouldn't it?? Most main switchboards, will actually be constructed to accommodate parallel feeds and in some circumstances even outgoing ways...

Not sure why you are obsessed with one leg failing, why would just one leg fail? Taking that all connections have been professionally made off, what would you say, is the chances of that ever happening??

I'm not obsessed with it. Just asking the wquestions that's all, as obviously there is something I have missed here!

 

[Engineer54]

I'm not obsessed with it. Just asking the questions that's all, as obviously there is something I have missed here!

Probably something else that's not covered in an electricians training these days... :sick: lol!!!

 

[Knobhead]

As an industrial electrician you must have come across a service head like this. A Lucy 630A unit (spreader boxes not shown).
View attachment 12183
If you can’t run parallel cables, why are there 2 cable outlets per phase.
As has been said in industry parallel cables are normal practice.

 

[J25GTi]

As an industrial electrician you must have come across a service head like this. A Lucy 630A unit (spreader boxes not shown).
View attachment 12183
If you can’t run parallel cables, why are there 2 cable outlets per phase.
As has been said in industry parallel cables are normal practice.

Yes of course I have seen these, but I've never used parrallel supplies etc. Only single cables up to 5 core 195mm. But we live and learn

 

[Knobhead]

Given the choice would you prefer to run a 185 or two 95’s. I know which my moneys on.

 

[Engineer54]

Yes of course I have seen these, but I've never used parallel supplies etc. Only single cables up to 5 core 195mm. But we live and learn

Are you convinced yet, that there is nothing wrong with a parallel circuit run?? And, ...can you now see the benefits that such circuits can bring to an installation, in both current carrying etc and cost savings in labour and cable costs??.... These can be very significant in larger projects, especially where long cable runs are involved...

 

[Brightspark2]

Good work, massive improvement there...


Once you start getting to larger CSA's, cables ran in parallel get more common for reasons already stated. Im just completing an installation in a data centre where we have run various cables in parallel, 2 x 185mm etc.

 

[Mark_Burgess]

Lets hope they have sorted the leak in the roof!!
What I would say is, it looks if the MCB they put in is the right way round, the MCB spring clip is supposed to be on the outside, well hager boards always state it.

 

[RISElectrical]

Cables ran in Parallel as stated are fine. If we worked on the principal of "when" a leg fails, a 2.5mm ring would either need to be on a 20A MCB or wired in 4mm as what your saying contradicts the design of a ring final circuit

 

[Knobhead]

We’re talking of power feeds to a MCC so possibly a 1200A feed. I don’t think it would fit in a CU.

Read through a post before commenting.

 

[RISElectrical]

We’re talking of power feeds to a MCC so possibly a 1200A feed. I don’t think it would fit in a CU.

Read through a post before commenting.

Correction, that's what you were talking about. The OP and indeed all the first page mention noting above 50A and 4mm. The attached pictures are of MCBs that 185mm wouldn't fit in to them would they?

I was merely making the point (someone else already made it earlier in the thread!!) about the principal of a ring so it relates to other areas as many people don't know about cables in parallel.

 

[J25GTi]

Lets hope they have sorted the leak in the roof!!
What I would say is, it looks if the MCB they put in is the right way round, the MCB spring clip is supposed to be on the outside, well hager boards always state it.

Yes I got a builder in to sort the leak from the roof, So we solved the problem and the cause of the problem, making for one very happy customer and then no future issues

 

[J25GTi]

Correction, that's what you were talking about. The OP and indeed all the first page mention noting above 50A and 4mm. The attached pictures are of MCBs that 185mm wouldn't fit in to them would they?

I was merely making the point (someone else already made it earlier in the thread!!) about the principal of a ring so it relates to other areas as many people don't know about cables in parallel.

This would be my college tutors fault (4 years ago now? jeez time flies)

As he always instilled the view on us that rings were inherently dangerous if you lost a leg etc then you have 2x 25a cables running on a 32a mcb etc. So this would be where i have formed this opinion from.

Obviously where practicable it would be better to use one single cable, but in alot of instances it obviously isnt practicable.

In the case of this supply i dont see why there is any reason to use parallel supplies for the length of cable it was just lazyness as they didnt happen to have any of the right size cable i imagine.

 

[Engineer54]

As he always instilled the view on us that rings were inherently dangerous if you lost a leg etc then you have 2x 25a cables running on a 32a mcb etc. So this would be where i have formed this opinion from.

Yet another collage lecturer that perpetuates his own personal views on to his students, ....inherently dangerous, what a complete plonker!! I wonder what he would of made of a 3 phase ring circuit that are commonly used in industry??

As for the parallel feed, not something i would have done myself, but never the less, fully compliant!!

 

[mark ju]

Parallel supplies are quite common as stated, but to get back to the original post, nice install, keep that up and i'd let you work with me!