PIR remedial advice.

[gselectrical]

Evening all.

I am in need of some advice regarding remedial work I am in the process of carrying out following a PIR by the clients insurance company.

The site is a tourist attraction consisting of various lighting effects and waterfalls etc.

A 3 phase board feeds 8 other boards. All armoured cable (everything underground)

Basically it is stated within the report that

"Two circuits were supplied from ways 1 & 3. These should be supplied from seperatly protected supplies"

Having had a look at this, I have found that they are lighting circuits. 2 cables in each MCB, each supplying a lighting control box. Now I personaly don't see anything wrong with this. If they are connected to the same MCB then surely they are 1 circuit? The rating of the MCB is adequate for the size of cable. Is there a reg that confirms what they have stated??

also;

"Both submersible pumps where supplied via the same MCB. They should be split up onto 2 seperate supplies"

Ok. Now these pumps are controlled by a control box linked to the CPU that controls "the show". So, basically an MCB supplies the control box and then the 2 pumps are fed from the control box. Again I do not see an issue here.

also;

"There are 18 submersible pumps within the installation, they do not appear to be provided with overload protection. It is recommended that the rating be identified in order for the requirement for overload protection be detirmined."

Ok. Surely the 10A MCB feeding the control box that the pumps are connected to provides adequate overload protection?

Any advice/opinions appreciated chaps!

GS

 

[sparkytim]

Was this a normal PIR limited to Non-complience with BS 7671 or Clients own specification?

 

[Sidewinder]

Circuits to MCB's no bother, except for "minimise inconvenience" reg.

PIR dubious

Pump TM O/L's should be in starter end of, linked into control system.

MCB don't count in this situation as it could be argued by a good brief BS7671 regs don't completely apply.

PIR spot on.

 

[gselectrical]

Circuits to MCB's no bother, except for "minimise inconvenience" reg.PIR dubious

Pump TM O/L's should be in starter end of, linked into control system.

MCB don't count in this situation as it could be argued by a good brief BS7671 regs don't completely apply.

PIR spot on.

Sorry mate could you clarify? TM O/L??? starter?

 

[Evans Electric]

Small motors such as those pumps generally don't have starters , protection via fuse/MCB only . Personally I can't see anything wrong with the job TBH .

Motors driving machines etc must have starters with no-volt release to prevent unexpected re-start and would incorporate O/L protection too .

 

[gselectrical]

A Thermal Overload normally fitted on a motor starterOr a motor protective circuit breaker (like a siemens 3RV or modeller PKZ)

---------- AUTO MERGE Post added at 21:44 ---------- Previous post was at 21:31 ----------

If the pumps are fed from a control panel then you may find thermal overloads of some sort in there, other contractor may have missed this if they didn't know.

What are the pumps for ? And what size are they ?

They are small single phase 110v submerible pumps (the sort you would have in your garden pond)

That is why I assumed the 10A MCB would provide adequate protection. The control board has various relays etc used to control the pumps.

They are used to pump water around the attraction (waterfalls etc)

Cheers.

GS

 

[Sidewinder]

Quite, this would not be the first time I had come across control systems adequatley protected "dissed" by electrical contractors who did not understand the system that they were looking at.

Sorry guys, but it is a real scenario I have seen.

There is one real situation where by an electrical contractor went into one of my customers without the correct authority, however, that is not the point.

They diagnosed a machine as faulty and dangerous, so I was called in to investigate/rectify.

There was nothing wrong with the machine the control system as they diagnosed it, it operated as designed and as per relevant legislation and standards with which it also complied. (7671 was irrelevant - that was the problem!)

However, they thought that they could get more work out of it by requiring DB's etc to be moved, machines rewired, motors rewound et al.

I was then asked to review their works by the H&S dept.

This resulted in the closure of the premises and the loss of jobs as I could not then ignore the issues they had brought up, however, if they had understood the equipment they would not have found fault and then the premises would be open & the people would still be in jobs.

Was it really dangerous, I don't know.

The customer was not willing to pay for a full PIR, and as they had had 2 reports in writing to say that this was required, they took the cheap option & closed it!

All because the contractor meddled with things that they did not understand.

I realise that this post may not be popular, but it is factual.

 

[Larnacaman]

Then you wouldn't need a starter or O/L protection as Deke explained....

Can't remember fully off hand but i think you only need to provide O/L protection to motors over .375 hp...

 

[Sidewinder]

it is 0.37kW.

However, does the brb apply?

What is the control system, do machinery regs kick in?

Are the pumps actually as per garden pond, NO, as they are 110V

Does the control system have inbuilt protection?

The O/L protection in the brb is only for the cable, motors almost always require T/M O/L as per manuf' instructions.

This should be designed into the control system which depending on age should comply with other statutory regs. 7671 aside.

 

[Larnacaman]

''Are the pumps actually as per garden pond, NO, as they are 110V''

Hummmm .....many a garden pond pump has a TX , some for 12, 24volt and some for 110volt.... I know because i have 2 here, German made, and bought in the UK!!

 

[Sidewinder]

OK, fair cop, however, garden pond pumps are not commercial items either, this is a commercial install, so...

 

[Larnacaman]

We do quite a lot of pump stations and pumping equipment and any motor ( regardless of the 0.37kw reg) we do a control panel for has both thermal and magnetic protection fitted to protect it. Any pump we do ( pump,meaning water in close proximity to electricity ) that doesn't come under skilled person control has an rcd fitted especially where the public are involved.

Very commendable Canoeboy. These days i think i would put any small, medium sized pump though an RCD.

I think were all over engineering this scenario now. It may be a commercial enterprise, but these items are not coming in contact with the public in any shape or form ....they are visual attractions as far as i can make out from the O/P

 

[Larnacaman]

Exactly my thinking, too much supposition on very little information. ..lol!!!

Again, they way i read the O/P was that these control boxes weren't only for ''one'' pump, and that the 10A breaker was feeding two of these control panels. How many pumps each control box is looking after, is again unknown!!!

I think I'll join you there, Guinness Cheers!!! lol!!!

Edit....

re-read the original OP post again and it seems two control panels 2 pumps, what else these control panels operate or control Who knows, but there seems to be 18 of these pumps in the installation, fed how and from where, .....again who knows ...lol!!

 

[gselectrical]

Exactly my thinking, too much supposition on very little information. ..lol!!! Again, they way i read the O/P was that these control boxes weren't only for ''one'' pump, and that the 10A breaker was feeding two of these control panels. How many pumps each control box is looking after, is again unknown!!!

I think I'll join you there, Guinness Cheers!!! lol!!!

Edit....

re-read the original OP post again and it seems two control panels 2 pumps, what else these control panels operate or control Who knows, but there seems to be 18 of these pumps in the installation, fed how and from where, .....again who knows ...lol!!

Ok, sorry for the lack of information. Got a call out after I posted last night.

Sub main from 3 phase board to each consumer unit within the installation. Each consumer unit has a 30mA RCD main switch. 1.5mm 3 core SWA then feeds a control box via a 10A MCB. This control box then feeds either 1x 110v trannie or 2 depending on the amount of pumps. Some control boxes control 1 pump, others 2. The pumps are then conected to the trannie with 2.5mm flex

All they do is simulate waterfalls at different times.

The public can not get anywhere near the water.

There are various relays etc within the control boxes which control the outputs.

Could these control boxes provide the adequate protection for the pumps?

Any further information required please let me know.

Thanks for the replys guys.

GS

 

[gselectrical]

See comments

The transformers they have used are normal site transformers.

I'll open one of the control boxes to get some pics.

Cheers!

GS

 

[Chr!s]

I see know issues with the information given.

The pumps will most likely have a thermal device of some sort which will protect the windings from over heating.

If your concerned about the pumps you need to get in touch with manufacturers or get manufactures info.

You have 230volt 1.5 cable protected by a 10 amp mcb, providing the relays and switches have a suitable rating then they should also be protected.

The trannies are 110 volt centre tapped, i assume adequately sized for the loads, each pump fed via 2.5 say 25amp rating, im sure the rating of these type of pumps wont be too high 400 watts tops so little chance of overloading 2.5 cable.

Think about it, 25 amp cable, protected via 10 amp mcb, 25 x 1.45 = 36.25 amp for one hour, providing the pimp has a thermal overload that wont happen and if it hasn't the primary side will see 17 amps so mcb will trip in less than 1 hour

So the 10 amp mcb is protecting all your cables.

I don't think the .37 KW will apply here, i would of thought the pump will have its own manufacturing standard and hence the requirement for at least thermal protection. And in that instance you could emit overload protection due to the type of load connected.

 

[Chr!s]

canoeboy

It will depend on the pump, some of the expensive pumps will have an internal thermal overload but this is normally a klixon which cuts out at a given rise in winding temperature (130 for an F wound motor with a B rise) related to the class in insulation the motor is wound to. A klixon is not a thermal overload like a conventional thermal or thermal magnetic overload thats fitted to a motor starter. Some do (not many) have a proper thermal overload internal in the windings, normally on small three phase pumps and they are normally wound into the star point connection to break all three phases with auto reset when the windings cool down.Agreed

And my view is if the pump is 0.37kw or more (which we dont know) then if it hasn't got an internal thermal protector (current not klixon (temperature)) it should have a thermal overload, which it may already have in the control box.

Well that would depend upon if it had a product standard or not, and what that standard stipulates

But like i said if it was a pump job we had done even a 0.09 kw pump would have a thermal / magnetic MPCB fitted to as as its just good practice.

Agreed

All that said, GS is there to carry out a PIR, now the only issue as far as i can see is whether the pump winding is protected against overload situation. The 10 Amp mcb is protecting the cable.

From the 110v pumps ive looked at, they do have a thermal cut out inside to protect the winding, and most seem to require a 13 amp 1362 fuse, which i suggest is for protection of the supply cable.

 

[gselectrical]

canoeboyAgreed

All that said, GS is there to carry out a PIR, now the only issue as far as i can see is whether the pump winding is protected against overload situation. The 10 Amp mcb is protecting the cable.

From the 110v pumps ive looked at, they do have a thermal cut out inside to protect the winding, and most seem to require a 13 amp 1362 fuse, which i suggest is for protection of the supply cable.

What are the options if there is no internal thermal overload protection and nothing incorporated within the control box?

Sorry, not done many pumps.

Cheers

GS

 

[binky]

If this is the pump manufacturers' control box, then it should all be CE marked as a system, and is probably suitable for purpose. If it is a made up box, which it sounds like, then it will need verifying what's inside it.

 

[gselectrical]

If this is the pump manufacturers' control box, then it should all be CE marked as a system, and is probably suitable for purpose. If it is a made up box, which it sounds like, then it will need verifying what's inside it.

Yep, def a made up box. Made up by the people who installed "the show" (all linked via data cables and controlled by a CPU)

cheers

GS