Any Electricians out there?

[Scrums]

Hi all,

Sorry to make this one of my very first posts, but I've managed to buy a 3 phase machine (Startrite 352 Bandsaw) at a giveaway price....but it's 3 phase - that I've got, but with an old fashioned socket and bare wires on the Bandsaw !

Can I just connect everything through a junction box initially and are there any wierd colour codes to watch out for ?

Cheers,

Chris.

 

[Adam]

You'll need to either A) Have 3 phase power installed to your house/workshop = mega bucks, possibly thousands.... or purchase a single to three phase converter (not sure on price, a few hundreds?). If you search the forum "search engine", with a term like three phase, you'll get all the information you need on recommended suppliers of phase convertors, and likely costs and things to watch out for.

Welcome to the forum.

Adam

 

[JFC]

Just twist the wires together and bobs your uncle . unfortunately you'll never meet him because you would have killed yourself by messing with 3 phase :lol:
Seriously 3 phase isn't to be messed with and defenatly not a DIY job .
hopefully someone will be along soon with some more constructive thoughts , welcome to the forum .

 

[Philly]

Chris
I really recommend that you contact a suitably qualified electrician about this-it's not worth messing up! :shock:
Cheers
Philly

 

[samlarsen]

Agree re contacting an electrician. Simple connection wont cost you much.

Dont understand why everyone so far is so scared of three phase. After single phase is three phase, just with two of the phases missing and a neutral. The extra voltage in three phase comes from the phase difference. The phases on their own are 240v.

You should consider; what breaker rating do you have in your supply, and does it suit the motor? Get this right as its vital to protect you and the machine. You could look at fitting an RCD to protect you and the motor is the best way.

How many wires do you have? Four including the earth?

3 phase motors will run backwards if the phases are incorrect so watch out for this on start-up ie flick test the motor to check direction (an electrician will do this). Running backwards is not a problem for your saw, but is a major problem for some pumps etc, as the drive is on a left hand thread to hold it all together. Spin them backwards and the pump is mangled.

Post back if you need any help.

 

[JFC]

Dont understand why everyone so far is so scared of three phase

Because were are not stupid :lol:

 

[Anonymous]

Chris

I am an electrical engineer

GET AN ELECTRICIAN IN AND DON'T MESS WITH 3-PHASE. IT IS 415 V BETWEEN PHASES!!!!!!

 

[samlarsen]

True, but people dont usually get a shock between phases, only to ground which is a mere 240v. Anyhoo it'll be good practace, due care and the RCD that saves ya in either case.

All irrelevant cos you are going to get an electrician arn't you, arnt you.

PS: make sure the saw is very clean, sparkies charge a lot more if they have to get any of their tools dirty. If it involves getting the electrician dirty, the jobs usually off!

 

[Midnight]

true enough..... most ppl don't get bit.... but when ya do...... trust me..... that chit hurts...!!!!! has some kick to it too.....

the way I see it scrums, you have 3 options...

have 3 phase installed (perfect solution if you're running a commercial shop)

use a phase converter (they work after a fasion but don't expect much from them)

replace the motor with a single phase that's suitably rated for the load. you'll probably still need a sparkie to do some installation for you in the form of a dedicated breaker, lockable isolator and hi current outlet.

 

[Scrums]

Thanks guys.......I was a bit apprehensive about having a fiddle on my own,as was her indoors. You've made my mind up - NO way!

I should have made it clearer - there is 415v in the workshop, just an old screw cap type socket and the machines I've bought were previously hard wired.

I'll get in touch with the landlords tame spark...

Thanks all.

 

[ike]

True, but people dont usually get a shock between phases, only to ground which is a mere 240v.

Oh yeah? An electrician I know accidentally dropped a screwdriver which shorted a contacter across phases - 415V gives a BANG!. You WOULD get toasted if it was part of you.

Ike

 

[samlarsen]

Saw the result of a spanner being dropped across some 415v busbars once. Punched the busbars straight out of the ends of the panel cabinet! :shock:

In neither case did anyone get electrocuted by getting between phases.

All this only proves one thing, anyone who is an silly person can electrocute themselves or others. So far this year I have thrown two electricians off site, one of which was for repeatedly cutting cables whilst live. Yep 3 phase. He was BS, ECS, NIC EIC etc, etc. He wont live long cos he's an silly person.

As I said, in truth 3 phase isn't any reason to get in a lather about as the risk of getting between the phases is very low. Its not any more dangerous to be around than single phase.

I'll give up gracefully anyway, have it your way ](*,) . That mans got 3 phase, run, run, run to the hills................ :roll:

Let us know if the electrician does anything other than puts a plug on it!!

Sam

 

[Anonymous]

True, but people dont usually get a shock between phases, !

Been there about 20 years ago. Landed 6 feet away on my back

 

[samlarsen]

So what went wrong? Did you get a packet cos, sorry, because;

A. You weren't taking good precautions?
B. Someone else wasnt taking good precautions?
C. There was 3 phases instead of one?

Since the last between phase shock you had was 20 years ago, then it looks like I might have been right to some extent - SHOCKS BETWEEN PHASES ARE VERY RARE.

Sam

PS - Did you go black and blue like my small australian friend who got a 450v DC belt a few years back. Have some sympathy, he took a door off the hinges as he left the room :shock: :shock:

 

[Anonymous]

Since the last between phase shock you had was 20 years ago, then it looks like I might have been right to some extent - SHOCKS BETWEEN PHASES ARE VERY RARE.
: :shock:

Not for 20 years because I was actually a technician at that point with ONC qualification and was fault finding on live kit in a difficult space.
I completed my degree soon after and became a design engineer - you know, the one who sits in an office tells others to get a 415V shock :wink:

 

[gwaithcoed]

I can tell you what happens to a cat when it steps on a 3,300 volt set of bus bars, as one did at the colliery that I was working at. It got in to the stator reverser of our winding engine through the cable ducts.

Used up all of its nine lives at one go. :shock: :shock: :shock:

Alan

 

[Neomorph]

True, but people dont usually get a shock between phases, !

Been there about 20 years ago. Landed 6 feet away on my back

Years ago I was on an electronics test and service mechanics course and we had to build our own stepper upper transformer boxes. We even had to make the open bottom boxes ourselves out of steel sheet.

Anyway the circuit board was bolted to the steel and kept seperate by plastic isolator sheet. One on my mates finished his quickly and hooked it up to the mains and got out his ohms tester. According to the output sockets he was getting nothing registering. So he turned the box over... or tried to.

As soon as he grabbed the box in both hands he became part of the circuit - BIG MISTAKE. It threw him backwards over the bench behind him and was lucky in that all he got was a couple of minor burns and a reminder to INSTALL THE DAMN ISOLATOR NEXT TIME! :lol:

Seriously though... If you don't know what you are doing then leave it to an expert and make sure it is an expert and not someone who "knows a bit about it and will have a go" as usually they are an accident waiting to happen.

 

[samlarsen]

Interesting point. A subject close to my heart.

Trouble is, achieving what you say "make sure he's a good one".

I would of thought the line of gathering more info on the situation surrounding the installation would lead to a few suggestions on how best to approach the new connection. Then the enlightened oringinal poster would then have had the tools to spot the more professional electrician from the more haphazard.

As I posted earlier there are plenty of highly qualified idiots around. How can we expect the home user to tell them apart if all we say is "pick up the phone book".

I dont know if anyone else is finding that some of our European cousins now employed here (following a quick part p course) have a slightly interesting view on the regs sometimes.

I'm beginning to think I might be on a crusade. Just been left to deal with an installation (tens of thousands of pounds worth) in which the highly qulaified electrician has "completed" the worst work I have seen in a while (homer) .

The EIC NIC test sheet is a mile long. Ignore me I'm crabby! :-({|=

Sam

 

[Nick W]

I can tell you what happens to a cat when it steps on a 3,300 volt set of bus bars,

A similar thing happened when I was doing a live broadcast on Radio4 one day, cat got into the local substation,big bang, out went the lights, and off went the organ. Strangely the little red light on the pole stayed on ...

We were still going out live as the Beeb was using some battery driven connection down a 'phone line. I don't think there has ever been another broadcast evensong using a piano for accompaniment.

 

[Scrums]

£300 poorer, but with 2 x unscathed electricians, brand new distribution board, conduits, isolators etc I can now play with my new Startrite Bandsaw and Wadkin Lathe.

Many thanks to all those of you who advised me not to go anywhere near 3ph electricity - you were quite right!

Chris.