installing 3ph and single ph wiring into new workshop

[kspray]

Ive got the task of sorting out the electrical supply to all the equipment and lighting in our bodyshop as we've just moved to a larger workshop

we have a new board installed with a 125A 3 phase supply installed, the first problem is that the board only has space for 4 circuits

we have the following to supply

electric shutter (10A fuse) 3ph

Spray booth with 2x 4kw fans 9A each 3ph

Compressor (info as on plate on electric motor) 3ph
5.6kW
18.2A/10.6A (might be wrong but im guessing the starting power required is the 18.2A and the continuous draw when running 10.6A??)

Welder 3ph (20A fuse fitted)



what was suggested to me was we should install a single phase board along side the existing one to then run all the single phase items, power points, lighting circuits

first question, the trunking carrying the cables around the shop, its positioned at 2000mm from the floor 50x50 does this have to be metal trunking, or is plastic suitable

who should be contacted to certify the system as safe when the installation is complete

also where will I find the regulations to follow for a commercial property such as ours?

I have done a number of CMS designs for LUL underground stations, but we were talking about huge cable trays with high voltage armoured cables so not really the same thing

finally, best place for me to order the cable, trunking, clips etc..

thanks

 

[ackbarthestar]

I assume that there are already circuits in situ?
If so the extra demand doesn't appear to be excessive although we would need to know what's there already
I would have thought that a 3-phase board with 12 or 18 ways would be perfectly acceptable. Why bother with single phase boards when you could balance the single phase loads across the 3-phases at the origin.

IMO Plastic containment system in a workshop would not be suitable. I would look at Galv. trunking.

 

[kspray]

the problem with the board is its brand new, the tight ar*e land lord put in last week and its only 4 way! and from what ive been told new 3ph boards are not cheap

at the moment there is on 13a double socket (wall) in the circuit and a small lighting circuit with approx 6 strip lights and the 3ph 10A roller shutter, all the lighting and power will be removed and redone with our new high bay lighting (single ph) and circuit of strip lights on walls and in the office and machine shop (single ph) and circuit of 13A double gang power points around the whole place and the 4 3ph items listed in the first post

so the thinking behind it was to use the board thats already installed to run the 3ph items and have a seperate dist board for the single ph circuits?

 

[ackbarthestar]

You will still need some load balancing of all the single phase circuits.
We are not talking excessive loadings, or size of incomer, or prices within this range
The prices of 125A DBs with Isolator are in the region of £200 to £300 ( Hager 16W = £218). Then breakers, RCBOs, RCDs, switchgear control on top.
You'd probably get the lot for less than £3k. A worth while investment if you are manufacturing. Obviously will also depend on the length of the lease.

 

[guest119]

Do you have insurance for design?

Boydy

 

[kspray]

Do you have insurance for design?

Boydy

nope, thats why it needs to be designed to the correct spec and then checked and certified

 

[somersetsparks]

not being nasty mate, but only a fool would 'check and certify' someone else's work and pass it off as their own. sounds like you need a larger TPN db, some 2x2 gAlv trunking, some steel conduit and a competent electrician to install it for you.

 

[Outspoken]

Ive got the task of sorting out the electrical supply to all the equipment and lighting in our bodyshop as we've just moved to a larger workshop

we have a new board installed with a 125A 3 phase supply installed, the first problem is that the board only has space for 4 circuits

we have the following to supply

electric shutter (10A fuse) 3ph

Spray booth with 2x 4kw fans 9A each 3ph

Compressor (info as on plate on electric motor) 3ph
5.6kW
18.2A/10.6A (might be wrong but im guessing the starting power required is the 18.2A and the continuous draw when running 10.6A??)

Welder 3ph (20A fuse fitted)



what was suggested to me was we should install a single phase board along side the existing one to then run all the single phase items, power points, lighting circuits

first question, the trunking carrying the cables around the shop, its positioned at 2000mm from the floor 50x50 does this have to be metal trunking, or is plastic suitable

who should be contacted to certify the system as safe when the installation is complete

also where will I find the regulations to follow for a commercial property such as ours?

I have done a number of CMS designs for LUL underground stations, but we were talking about huge cable trays with high voltage armoured cables so not really the same thing

finally, best place for me to order the cable, trunking, clips etc..

thanks

Do you already hold nationally recognised qualification in Electrical Installation work?

If you are a qualified sparky then please ignore my comments below, if you are not, then read them several times.

This is a commercial premises, if you are not a fully qualified electrician then working on it is an offence under the Electricity at Work Act, further, being a workplace, do you have someone there with electrical qualifications who can undertake a complete set of RAMS for the job, failure to do this will be a material breach of the Management of Health and Safety at Work Act and the Health and Safety at Work Act. A breach of any of those is a guaranteed prosecution these days. Further, if you are interfering with the supply into the building then you risk prosecution under several other Acts too if your not qualified or authorised to do so.

400V 3 Phase KILLS, it can give you flash burns, set your hair on fire, burn your skin to the bone and cook your organs if you get this wrong. You could burn down your unit if you get this wrong.

Don't be a fool, get someone in who is QUALIFIED, EXPERIENCED AND INSURED TO INSTALL SUCH SYSTEMS INTO YOUR PREMISES. Doing it on the cheap is a fools errand and false economy, if this is a legitimate registered company then the costs are tax deductible, as your accountant will tell you.

Don't risk your life or those of others so save a few pounds.

 

[kspray]

Do you already hold nationally recognised qualification in Electrical Installation work?

If you are a qualified sparky then please ignore my comments below, if you are not, then read them several times.

This is a commercial premises, if you are not a fully qualified electrician then working on it is an offence under the Electricity at Work Act, further, being a workplace, do you have someone there with electrical qualifications who can undertake a complete set of RAMS for the job, failure to do this will be a material breach of the Management of Health and Safety at Work Act and the Health and Safety at Work Act. A breach of any of those is a guaranteed prosecution these days. Further, if you are interfering with the supply into the building then you risk prosecution under several other Acts too if your not qualified or authorised to do so.

400V 3 Phase KILLS, it can give you flash burns, set your hair on fire, burn your skin to the bone and cook your organs if you get this wrong. You could burn down your unit if you get this wrong.

Don't be a fool, get someone in who is QUALIFIED, EXPERIENCED AND INSURED TO INSTALL SUCH SYSTEMS INTO YOUR PREMISES. Doing it on the cheap is a fools errand and false economy, if this is a legitimate registered company then the costs are tax deductible, as your accountant will tell you.

Don't risk your life or those of others so save a few pounds.

read the above and totally agree, ive got a friend who does these installations for a living, I saw him yesterday for him to come and have a look, we will be using him for the install and design, im trying to get as much ready for him as possible, hes not available for a few weeks and we are on a tight schedule so if i can get the trunking installed where hes suggested, and power points in place etc while im having the walls and floor decorated so all he needs to do is run the cabling and set everything up

theres no way i was even contemplating the install, just like to know what to expect and what im dealing with

really appreciate all the replys

 

[Engineer54]

I hope your friend isn't contemplating using that silly 4 way TP&N board (that the landlord had installed) with an additional single phase DB/CU. As sure as eggs are eggs, a month after it's all been installed, you'll need another 3 phase supply!! Replace that small 3 phase DB and and install a 3 phase DB of suitable size to accommodate the existing 3 phase and single phase requirements, with further capacity for any future 3 phase loads etc....


With vehicle workshops, especially those with spray booths and welders etc, it would be pure folly to install a PVC trunking system as your containment. Keep it an all metal containment system. You'll be far better off all round, for both mechanical and electrical protection....

 

[Darkwood]

Reading your OP its clear 3ph is not your comfort zone.... you are making wrong assumptions regarding the motors ....I suspect its a duel voltage motor and the amp rating are respective to the voltage - the start up current will be approx' 6-10 times the running current and correct sizing and mcb fusing is essential to avoid tripping on start-up. You mention a spray booth... if this is used where explosive gases may build up then regardless of how they had it set up before you will be required to ensure that any electrics is in compliance with respect to explosive atmospheres.... ive seen the set up before where a small garage has moved and his spray booth was very makeshift and non-compliant .... as already mentioned your dis-board is physically too small and that's the hard truth it needs upgrading, if your even asking who should be contacted to certify job then IMHO this job needs to be done by a competent Electrician knowledgeable in 3ph installations and requirements regarding spray booths.... I see this project costing many thousands more than anyone at your end first perceived.

 

[Outspoken]

Ive got the task of sorting out the electrical supply to all the equipment and lighting in our bodyshop as we've just moved to a larger workshop

we have a new board installed with a 125A 3 phase supply installed, the first problem is that the board only has space for 4 circuits

we have the following to supply

electric shutter (10A fuse) 3ph

Spray booth with 2x 4kw fans 9A each 3ph

Compressor (info as on plate on electric motor) 3ph
5.6kW
18.2A/10.6A (might be wrong but im guessing the starting power required is the 18.2A and the continuous draw when running 10.6A??)

Welder 3ph (20A fuse fitted)



what was suggested to me was we should install a single phase board along side the existing one to then run all the single phase items, power points, lighting circuits

first question, the trunking carrying the cables around the shop, its positioned at 2000mm from the floor 50x50 does this have to be metal trunking, or is plastic suitable

who should be contacted to certify the system as safe when the installation is complete

also where will I find the regulations to follow for a commercial property such as ours?

I have done a number of CMS designs for LUL underground stations, but we were talking about huge cable trays with high voltage armoured cables so not really the same thing

finally, best place for me to order the cable, trunking, clips etc..

thanks

I think I have made my thoughts perfectly clear on this matter, but if you want advise anyway...

Main board: 12 Way 400V 3 Phase Schneider Isobar board (The Old Merlin Gerin boards)
Isolator: 125A TP&N

3 Phase Services:

All services supplied via SWA unless you fo to the expense of running trunking as you suggest you may.

• Shutter Door: Supply via a 10A TP Type C MCB feeding a 16A 400V 4P+E Ceeform socket (if the drive does not require a neutral this can be changed to a 3P+E) (Ensure this is one with an inbuilt isolator but not RCD)
• Spray Booths: Supply via 6A TP Type D MCB feeding a 16A 400V 3P+E Ceeform Socket. (Ensure this is one with an inbuilt RCD) (The actual load on 400V of these units is only 5.7A per phase)
• Compressor: Supply via 10A TP Type D MCB feeding a local Isolator, this should then feed a 16A 3P+E Ceeform socket. (5.6kW @ 400V = 8.09A per phase)
• Welder: Supply Via a 20A TP Type D MCB feeding a local Isolator. This should then feed a 32A 3P+E Ceeform socket.

You then have 8 spare 3 phase ways or 24 single phase ways. Ensure all single phase services are spread across the phases, calculate the load and spread them, do not simply put 4 on each phase as this is the IT engineer method of balancing and doesn't work. Do not forget to get blanks for ways that are not used. Ensure you have a clear chart for the DB so anyone can clearly identify each and every way in the board.

As I said before, get a fully qualified spark in to do this who has Industrial Experience.

 

[Darkwood]

Not sure where you get your motor ratings from Outspoken but a 5.6kw compressor would be approx. 11amp flc and if your using merlin mcb's then either a 32(b), 32(c) or a 16(d) will ensure no nuisance tripping from start-up inrush.... not sure where you got 8.09amps from when OP has already given plate rating of 10.6amps ( I expect the other amp rating is for a different voltage set-up). As the theme of the thread goes though its something like your post he needs im just concerned the spray booth may require external electrics or intrinsically safe gear ...... too little info as normal.

 

[Outspoken]

Not sure where you get your motor ratings from Outspoken but a 5.6kw compressor would be approx. 11amp flc and if your using merlin mcb's then either a 32(b), 32(c) or a 16(d) will ensure no nuisance tripping from start-up inrush.... not sure where you got 8.09amps from when OP has already given plate rating of 10.6amps ( I expect the other amp rating is for a different voltage set-up). As the theme of the thread goes though its something like your post he needs im just concerned the spray booth may require external electrics or intrinsically safe gear ...... too little info as normal.

Maths.

5600/(1.73*400) = 8.09A

Unless you have figured out a different way of working it out...clearly you need to take into account pf but the MCB would be sufficient for taking that into account anyway.

Why would you put it on a 32A breaker FFS...?? rate the protective device properly, that is why they are typed!!

 

[Darkwood]

I realised how you got your answer but you missed the PF off your calculations which makes a big difference when choosing the correct mcb.


I = P / ( 1.73 * V * p.f)
I = 5600 / (1.73x400x0.8)
I = 5600 / 553.6 .......I get a ball park of 10.12amps using an average 0.8 pf which more or less tallys with his plated flc value and my tabulated tables of KW rating conversion tables.


If on site though i just double the KW rating for a ball park and this allows for PF and can give a figure on demand of an install before i go and do all the calculating where motor flc isn't supplied.