Electric Shower

Discussion in 'Interference Problems' started by Stephen Reading, Nov 15, 2017.

  1. Stephen Reading

    Stephen Reading New Member

    My transmissions trips the fuse switch in the main fuse box. Background. I went QRT some 31 years ago and have now returned to the hobby. My original HF rig was a Trio 599 Custom Special twins (M). I had a vertical outside the house and I had a 10, 15 and 20m wire trap dipole inside the roof space.

    I now have a Yaesu FT991A transceiver. I do not use the internal ATU but purchased an LDG ATU.

    For a short while I have been operating with what I believe t9 be the old wire trap dipole which unfortunately had been disturbed when loft insulation material was installed. A short while ago that trap dipole was rehung correctly.

    My shower is in the bathroom on the upper floor and the fuse box is on the ground floor under the stairs. The shower is fed via the correct 250VAC cable up to the roof and down to just outside the shower room to an on-off switch. The cable feeds into the electric shower through plasterboard into the shower cubicle.

    Each time I tune up or just transmit the fuse in the fuse box downstairs trips and power is shut off and hence the shower will not operate.

    Has anybody encountered this problem and solved it?
  2. Ken G3SDW

    Ken G3SDW Moderator

    Hi Stephen from your description i would say that your are getting RF into your mains system and with your antenna being in the loft along side the mains cable for your shower then this is most likely to be the cause.

    What is the SWR of this antenna when using it? and you say that you believe your antenna to be an old wire trap dipole, you dont sound sure.

    What bands are you using when this problem happens?

    Have you tried to see if you have the same problem when using a dummy load.

    Finally you say that your original rig was a Trio 599 custom special, are you sure as this is a Receiver not a Transceiver, could you tell me what your call sign is please.
  3. Stephen Reading

    Stephen Reading New Member

    Ok Ken

    First - the callsign is G4LZD

    The beginning of my post related to the background: You will note that I did identify my original rig as Trio 599 Custom Special TWINS - I perhaps should have mentioned that they are still in storage. I have no need of them.

    In the mid eighties I had a number of wire dipoles in the loft including a Moseley TD3Jr trap dipole (wire version). The guy that sold me his Trio 599 twins then offered me a trap vertical which I bought and then relied on. I forgot all about the wire trap dipole in the loft until I restarted the hobby about 3 months ago. I had got rid of the trap vertical when I gave up the hobby. A friend (another amateur) helped out intending to go up eventually into the loft and rig something up there (as I am no longer fit enough to crawl around the loft). I still had coax feeders down into the shack and he tested those initially and found that there was one coax which showed good continuity and we surmised it was that Moseley trap dipole (which turned out to be correct). I used that temporarily with very good results. The shower was unaffected by my transmissions on 10, 15 and 20 metres. When Dave went into the loft he found that one half of the dipole was hung where it was originally placed but the other half was coiled haphazardly and hidden under loft insulation (not my doing but the professional insulation installers).

    Problems only started when the coiled half was re-hung where it should be.

    With the external ATU I have SWR 1: up to a maximum of 1:3 -1 on 10, 15, 20, 40 metres and I am still testing other bands. I know the shower problem exists on those bands.

    To further clarify - it is only the earth residual switch linked to the shower that trips - not tripping everything in the house - all else remains fine.

    I have a friend who is a retired Naval Architect and I spoke to him today about my problem. On military ships he has designed they have encountered similar problems arising from RF invasion. He said that the Naval Architects solution was to screen cabling using Aluminium Foil (the baker`s kind)
  4. Ken G3SDW

    Ken G3SDW Moderator

    Think what you need to do before anything else Stephen is to, and assume that there is not one and that is to fit a 1:1 balun at the feed point of your trap dipole, as all often is the case is that when you feed a balanced antenna with a unbalanced cable you get RF voltages set up on the outer of the cable, and in your case with the mains cable to the shower being one of then longest there then it s picking up RF from your feeder cable.

    Your friends idea of screening all the feeder cable is fine if you want to go down that road but that will not be an easy thing to do and i honestly feel it will not sort out your mains tripping.

    You say that the dipole is for 40,20,15 and 10M and you are testing other bands, what bands would they be.

    Oh yes and by the way i located your call sign earlier today on QRZ.com

    Look forward to your reply.
  5. Ken G3SDW

    Ken G3SDW Moderator

    Stephen, just been looking at your QTH on google maps and would like to know two things, 1. How long is your trap dipole? and 2. how big is your loft?

    Not that this should be so much of a problem as i also have HF antennas in the loft of my small bungalow and i also have a very long mains cable feeding my shower and running full 100 watts do not have any problems at all.

    This should also apply to you so other than something wrong with the actual trip switch then without a doubt you have excessive RF voltages present in your loft space.

    What is the SWR on each band without using your LDG tuner? as most modern day tuners will match most things connected to it, have you taken down the trap dipole and checked all the connection including the traps and centre feed connections.

    I need to know all these points so i can identify what your problem is so to try to help you eliminate it.
  6. Stephen Reading

    Stephen Reading New Member

    Ken. I have two radio amateur friends, G3WCB and G4VHL and we formed ourselves into the West Dart Radio Group (just a casual group) and we meet on a Friday in the Sainsburys store in Dartmouth. I had a couple of hours with G4VHL (he is the one that induced me back into the hobby). He and I noted your advice about the balun and Bob thinks that is a good idea.

    Just to clarify the whole problem: I have two EMC problems - the shower being one and the other when I tune or transmit my internet drops out (telephones unaffected). I should also mention that G3WCB discovered that I also had a straightforward 10m dipole which had been taken down. He rehung that one.

    So far as the internet is concerned, I may be the author of my own misfortune but we are going to live with that for a while. So far as the shower is concerned, all I have to do is to switch off the shower and switch it back on again when the shower is needed. It is just that it is happening and it (to use the expression - it is getting up my nose).

    That all said, before the trap dipole (and the single band 10m dipole) was rehung and repositioned, the shower was unaffected. Bob says before we get too deep into `doing this and that` we should reposition the trap dipole (to V shape) well away from the mains cable feeding the shower and take down the 10m dipole. If that doesnt solve the problem then we think again.

    The pitch of the roof is a problem. You cannot stand up in the centre. If you were to go to Google maps and put in my address, you should be able to click on the image and `go walkabout` (as they say) and see the pitch of the roof etc - it`s the gable end of my semi-detached house)
  7. Ken G3SDW

    Ken G3SDW Moderator

    Hi Stephen, yes i have already looked at you house and can see the restrictions you have in your attic.

    I know the area very well and you road extremly well along with the type of house you live in as i lived ans worked in South Devon for 25 years doing house calls on a daily basis.

    I think that you need to seriously look at you antenna which has been in the attic for some time, connections do deteriorate and whilst talking about antennas how long is this trap dipole and is it in a straight line or bent around the timers.

    At the end of the day you seem to be in good hands so i will close your case and hope you along with you colleagues solve you problem.
  8. Stephen Reading

    Stephen Reading New Member


    Many thanks but do you think you can keep the case pending for a little while?

    I am going to the Plymouth Rally tomorrow with G4VHL and G3WCB and I can chat again with them. We will of course look at the connections anyway because G4VHL said that we might reverse the braid/centre core of the coax feeder.

    I cannot say how long the trap dipole is because it was 31 years ago I put it up there when I was fit and able to crawl around. I will see what the other guys say (if they know it).

    The present position is that the trap dipole is in a straight line almost corner to corner. G4VHL is talking about bending it V shaped away from the mains cable. He has an all singing, all dancing antenna analyser which he can employ to see what happens when we do that. In his view it is a matter of experimentation. In the interim he did suggest I put a question on the Forum which I have done.

    Intriguing: wonder what you did in South Devon Ken - making daily housecalls???

  9. Ken G3SDW

    Ken G3SDW Moderator

    I can see what you colleagues are trying to do but by doing this with such limited space then you will not achieve nothing at all.
    A analyser is all very well but will not tell you what your problem is but all i can say is use a 1:1 balun at the centre once you have ascertained that the antenna its self is in good shape, your friends mean well but i cannot see that you will achieve your goal which is to stop the trip tripping.

    Your problem is the most basic one where this sort of problem is happening and with the proximity of everything in the attic then you must have everything equal, so far it is far from that.

    Your last question is for another day.
  10. Stephen Reading

    Stephen Reading New Member


    The one point you seem to have overlooked is that the shower did not trip until the antenna was re-hung. With only half in the proper position and the other half strewn about I have worked 41 countries in just a few months and I have not been going at it like a bat out of hell. It has to be resolvable.

    I do, incidentally, have a vertical yet to be mounted outside the house on the gable end wall. For the moment I want to be less conspicuous but in any event, something not being right, there is a desire to try and fix it. If at the end of the day, the vertical goes up, works fine and produces no external problems (or internal ones for that matter) then I might just abandon the trap dipole. There is always the option of relocating outside


  11. Ken G3SDW

    Ken G3SDW Moderator

    Well if that is the case then thats all the more reason you should take it down and inspect all the traps and associated connection.

    At the end of the day if you have the option of erecting your vertical outside then do not waist any more time trying to get a trap dipole working OK in the loft get the vertical antenna outside as loft antennas can work but also can cause other problems being in close proximity of all the house wiring mains cables

    But back to what you have said, if it did not give you trouble before when it was coiled up but now stretched out it does then investigate why that is, you must have disturbed a bad connection, the shallowness of your attic means that no matter what position it is then that will not make any difference to its operation or in your case cause your mains trip to trip.

    Have a great trip to the Plymouth rally tomorrow and if you bump into any of the lads from the Torbay club give them my best 73
  12. Stephen Reading

    Stephen Reading New Member


    Just an updateL

    No, the shower issue is not yet resolved.

    I did attend the Plymouth Rally and bandied your name around.

    G3WCB of course knows you having worked you.

    You will recall I had another issue: My internet being disconnected when tuning the ATU or transmitting on all the bands I can operate. That issue has been resolved on advice from G6GLP. I would attach an article he sent down by e-mail following the rally. G3WCB made the filer up in an hour or so from bits and pieces he had in his junk box. It works on ALL BANDS. No more disconnection. I cannot upload the information here because the system claims ignorance (it is a simple Microsoft Word document)

    Regards and 73`s
    Stephen G4LZD
  13. Ken G3SDW

    Ken G3SDW Moderator

    Thanks Stephen

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