Dave22 Posted June 9, 2012 Share Posted June 9, 2012 So to all you event electricians/technicians what can we do about 125a 3phase ceeforms. We have a very good maintance routine at our company but on some occasions we find 125a3 getting hot or burning out even with half the rated capacity loaded on the connector. I am aware you can t run full load on the connection indefianlty but I am uncertian how long and how much load you can run on these connectors. Im fully aware of loose connections having an affect and dirty pins and sleeves, infact on most jobs we tighten the connections and clean the connetors every gig if possible and have a simple way of marking on the connector with a sharpy and intials when it was last checked and by who. We have found limiting the amount of connectors obviosley helps as its another connection removed from the circuit, I have found in my limited 10years working with temporary power and Managing the power for small and large events we always seam to have the same occasional problem on the odd show and the 125a 3phase connector is beging to annoy me now! I was curious if fellow blue roomers have had the same issue or have a simular experiances? We use mekkenes connectors which I belive are the most suitable as they are durable easy to take apart easy to maintain and most importanlty have allen key grub screws to clamp the cable. Short of running 50mm powerlock every where and changing to mini powerlock I am out of ideas! Link to comment Share on other sites More sharing options...
jonathanhill Posted June 9, 2012 Share Posted June 9, 2012 I too have had a couple of 125/3 connectors weld themselves together. All connectors have a duty rating, but the 125/3's seem to be the worst. Personally I hate 125A in single and three phase, mainly for the weight of the longer lengths. I would rather run PowerLock and jump down to 63/3. I am intrigued by what you mean by mini PowerLock as I thought that they came in one size but two capacities. Link to comment Share on other sites More sharing options...
themadhippy Posted June 9, 2012 Share Posted June 9, 2012 could this be down to exesive neutral currents? Link to comment Share on other sites More sharing options...
JDLX Posted June 9, 2012 Share Posted June 9, 2012 You are balancing the 3 phases equally I assume? Link to comment Share on other sites More sharing options...
tokm Posted June 9, 2012 Share Posted June 9, 2012 I think the OP's talking about Snaplock connectors? Pretty rare in my experience.. Can't I've seen any outside of modular dim/hot rack systems such as the ones below. http://www.gslpower.com/images/galleries/pwc720IMG_1716%20(1).jpg&http://www.gslpower.com/images/galleries/cfh33kIMG_0789.jpg No reason not to use them on temporary systems, just might struggle to find anyone else who stocks them, should you ever need more. Link to comment Share on other sites More sharing options...
adam2 Posted June 9, 2012 Share Posted June 9, 2012 AFAIK a 125 amp ceeform SHOULD be able to carry 125 amps continually.I would however agree that these connectors can not in practice be relied on to carry full load, or even 100 amps continually.Simply a poor design IMHO. For regular use at 100 amps or more I would favour powerlock. If ceeforms must be used, then all one can do is regularly check the connections and that the mating surfaces are kept clean.Also give very careful attention to the cord/cable grips. If these do not grip the outer sheath of the cable tightly, then any flexing tends to loosen the conductors. I doubt that excessive neutral current is relevant. In a single phase circuit the neutral current cant exceed the phase current..In a three phase circuit, the neutral current can in theory exceed the phase current, but very seldom does in practice. Link to comment Share on other sites More sharing options...
Jivemaster Posted June 9, 2012 Share Posted June 9, 2012 I vaguely recall seeing a brush system for cleaning ceeform pins and socket tube mating faces. There was some data to show that a "in service" ceeform had more tarnished contacts than a "clean as new" ceeform meaning that cleaning the contacts prevented heat build up. How much was fact vs marketing I never knew but for the limited cost (cf a 125A 5 pole ceefotrm) it may be a good idea. Link to comment Share on other sites More sharing options...
bigclive Posted June 10, 2012 Share Posted June 10, 2012 It's not just tarnishing. Mud, grease, dust and general event goo is a big factor in increasing the resistance of a contact and leading to failure. I strongly advocate the occasional walk round a job feeling all the connectors for heat, since heat usually indicates a resistive connection. Thermal imaging cameras are quite handy for viewing a lot of equipment at once. (Although they are rather expensive.) Link to comment Share on other sites More sharing options...
Tomo Posted June 11, 2012 Share Posted June 11, 2012 In a three phase circuit, the neutral current can in theory exceed the phase current, but very seldom does in practice.This isn't an environment where the loads are reasonably balanced and 'simple' with few harmonics. In a three-phase theatrical dimming system, neutral current exceeds live conductor current very often because the loads are never balanced (thus high neutral currents anyway), and there are significant harmonics some of which 'add together' in the neutral. Electricians who believe that neutral currents are small and don't exceed the live current have caused many faults in theatres and other places where large amounts of SCR dimming is used. A burnt-out neutral is also a very expensive fault! It's also starting to become an issue in office and classic industrial environments as the loads get much less 'simple' - VFDs and three-phase AC-DC converters for motors, electronic ballasts for lighting, more and more SMPs...The loads just aren't resistive anymore. Link to comment Share on other sites More sharing options...
Brian Posted June 11, 2012 Share Posted June 11, 2012 By way of background info... To meet the European standard, a 125A connector, wired in 50mmsq cable, should not exhibit a temperature rise of more than 50K when subjected to full load for 2 hours. Link to comment Share on other sites More sharing options...
dbuckley Posted June 11, 2012 Share Posted June 11, 2012 The USA National Electrical Code requires 200% rated neutrals, precisely because neutral currents often exceed any phase current. It's a good model. Hence six wire camloc and lug cable assemblies. Link to comment Share on other sites More sharing options...
Oovis Posted June 11, 2012 Share Posted June 11, 2012 To meet the European standard, a 125A connector, wired in 50mmsq cable, should not exhibit a temperature rise of more than 50K when subjected to full load for 2 hours.A rise of 50 Kelvin? Eek. I don't think I'd want to be handling that on a warm day... Link to comment Share on other sites More sharing options...
timsabre Posted June 11, 2012 Share Posted June 11, 2012 To meet the European standard, a 125A connector, wired in 50mmsq cable, should not exhibit a temperature rise of more than 50K when subjected to full load for 2 hours.A rise of 50 Kelvin? Eek. I don't think I'd want to be handling that on a warm day... rise of 50K = rise of 50C... I suppose that could be burnt finger time. Link to comment Share on other sites More sharing options...
Stuart91 Posted June 11, 2012 Share Posted June 11, 2012 Where is the temperature rise measured? On the outer casing or on the connection itself? Link to comment Share on other sites More sharing options...
Brian Posted June 11, 2012 Share Posted June 11, 2012 Where is the temperature rise measured? On the outer casing or on the connection itself?The terminals themselves. Link to comment Share on other sites More sharing options...
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