Best HV connector

The following discussion about the best High Voltage Connector took place in the Moon-Net reflector. I found the subject so interesting that I decided to put together all the messages in this page.

On 15-May-2003 PA1BVM wrote:
My PA on 144 consists of two boxes , the cpower supply and the " cavity" At this moment the Anode HV cable is hard wired via a piece of RG213 from one box to the other .

I was thinking of making a connector in the HV cable so that I can use the same power supply for other " projects" The power supply for the Anode delivers about 2.5 KV could I use a N-style connector or Spinner to connect HV ?? Anybody using it what are the safe " limits" for these kind of connectors .

Was loolking arounf on the " web" but HV connectors are difficult to find around JO21 square

On 15-May-2003 W2DRZ wrote:
I think a safer method is a HN connector for the want of a better HV device..

want to use a back up HV ground/wire if using coax to supply HV and ground, very dangerous as the coax ground/brade can become disconnected..

On 15-May-2003 Holger wrote:
In my opinion it is no good idea to use a male plug at the hot end of a HV cable. I have seen and worked with a PA using RG213 with PL/SO259 connection for the HV. I think it is quite dangerous to operator such a PA e.g. on a Fieldday or Contest such a PA. This voltage can kill...

May be u find some real HV connectors at a fleamarket. Weinheim? :)

On 15-May-2003 W2DRZ wrote:

can parallel the HV and ground to other amps at the same time from power supply, just bias off the unused amp or leave it turn off if not using it at the time, it is a common thing, just be aware that the plate circuit is hot with B+ so don't be working on the other amps, be best to install safety micro switches on all amps to disconnect the HV turn on circuit for you health and safety..

On 15-May-2003 DH5HV wrote:
Hey Rick

If you have the same connector on the HV cable than somewhere else in the shack, think about that:

It would be very interesting to see the action in the shack if 2.5KV reach on a little variable input-"C" for example from you 2m-PA...!

Or worst case: You take the HV-cable with the N connector and put it to your TRX...........!

I know, you won?t be so silly yet, but how about tiried periods or very busy times when everything has to be done quickly.....!

Better to use annother connector than you normally use in your shack !

On 15-May-2003 Guenter wrote:
my few cents...

witout problems for years, i used insulated 4mm connectors from laboratory equipment. up to 4.5kV and 1A without problems, even laying on the floor and walking across these cables.

and in fact it was like dh5hv says: I nowhere else used these connectors...

On 15-May-2003 M0MAT wrote:
If you visit and do a search for PET 100 you'll find the connectors that'll make a proper job of it.

They're not cheap, plugs 24euro, sockets 45euro !

Solid core RG59 fits into them nicely, but it's worth checking that the spec of the RG59 you get hold of, as it varies from one type of RG59 to another.

On 15-May-2003 PB4CC wrote:
Do not use N-connectors.

There are special High Voltage look like BNC connectors, with a longer teflon insulator on the soldersides, also inside on the male and female pins it have a better teflon insulation (much better then N-connectors). Cable what I use is RG58 with 4kV. The HV BNC fit NOT on an ordinary BNC connector due to the extra teflon screen inside.

On 15-May-2003 SM2BYA wrote:
If you are prepared to spend some money to feel safe, you could go for the professional solution:

RG-59B/U cable with type SHV connectors.

SHV stands for Safe High Voltage. It is the standard HV connector series used in nuclear/particle physics high voltage gear and other professional HV equipment nowadays. This connector series is rated to 5 kV and designed to take RG-59 type cables only. The bayonet part of an SHV is identical to that of a normal BNC. SHV plugs have a protruding teflon sleeve that makes it next to impossible to get in accidental contact with the center pin, which is recessed about 15 mm into the connector. It is also impossible to plug it into a normal BNC jack.

Quote from the Amphenol website:

"... These (MHV,SHV) are high voltage versions of the BNC. The SHV was designed to replace the MHV. It was felt the MHV was an unsafe connector since the ground connection was broken before power connection. The SHV was developed by NBS for high energy physics applications. Both series were recently incorporated into Mil-C-39012, however, the MHV series was immediately inactivated and replaced by the SHV. MHV connectors were covered by Mil-C-39012 slash sheets 100 through 104. SHV connectors are covered by Mil-C-39012 slash sheets 105 through 111. Both MHV and SHV were not designed with the intentions of meeting RF performance parameters."

I have been using RG-59B/U with MHV, and later SHV, connectors for all my HV cabling since the early 1970s at voltage levels up to 4.5 kV. In the mid 90s you could still get SHV connectors from Ericsson here in Sweden, but not any longer.

The UK Digi-Key website lists a range of SHV plugs and sockets at around 23 pounds each in small quantities. Expensive ? I don't think so - your life is your most precious commodity after all...

On 15-May-2003 OK1DFC wrote:
K1FO in his PA has this HV BNC and also sale this article. I have some BNC on my PAs without problem long time.

On 15-May-2003 PA2DWH wrote:
I confirm Peter's reply. I am using these "HV-N" for years and had many flashovers, but never in the connector hi! Rick, you can probably get these connectors at Quackelstein/Vlaardingen.

On 15-May-2003 WA4NJP wrote:
I use this connector. MHV is the designator it is rated at several anps up tu 5 KV. I do use RG59 with solid PE insulation.

On 15-May-2003 Steve wrote:
>>If you visit and do a search for PET 100 
>>you'll find the connectors that'll make a proper job of it. 

PET connectors are no safer than BNC or N type; the centre pins are easily touched - they're not cheap either. For the same price you can get BNC - SHV connectors, which have proper insulation clearances and also guarantee that the outer makes contact first and breaks last. Ratings are 12kV and 10A. How much is your life worth?

Look up your local outlet for Suhner or Rosenberger and ask if they will sell to you, or you can buy from RS components in the UK.

On 15-May-2003 G0RUZ wrote:
Use SHV or MHV connectors, they are safe and will handle 10kV @ 2 amps. They are available from RS components and are listed as BNC high voltage. They do not mate with standard BNCs so there is no danger of silly mistakes.

On 15-May-2003 WA4NJP wrote:
I hope we as an experienced group use an approiate connector for the voltage and current. Even if you use the $$$$SHV don't connect or disconnect with the HV on. Back when.....the old Millen HV connector was the standard. it did'nt take but one time at handling those things to realy give you an education, and a burnt hand. Be carefull......

MHV and SHV are both shown in the Newark Electronics Calalog or on line at and use search.

On 15-May-2003 G3SEK wrote:
Unfortunately MHV *will* mate with BNC - a silly mistake for a connector that's supposed to be designed for HV.

SHV are definitely the ones to use. They won't mate with anything else, the centre pin is deeply recessed inside both parts of the connector, and it makes a reliable ground connection *before* the HV pins come into contact.

As Steve says, how much is your life worth?

On 15-May-2003 LA8AK  wrote:
In my opinion it is better to have the plug "on the cold side" - meaning that I would use a C-connector on the cable to the power supply - not to the PA. Since C-type connectors are impractical for all other purposes here I would choose it. It is easy to obtain C-connectors and ready made cables with C-connectors in smaller quantities. But the way some amateurs mount coax cables it isn't safe whatever way you use them.

I already use N-type, PL259/SO-239, BNC types since they are already mounted on equipment, also use TNC for some control lines, so I see no reason to mix up with them.

On 16-May-2003 K1FO wrote:
Just to echo what others have said on HV connectors.

Do not use type N connectors. N connectors are only rated for 1500 VRMS

Also as someone else has stated, you run the risk of accidentally connecting your N connector with HV to someplace it doesn't belong.

Do not use Millen HV connectors, they are dangerous as Ray has said. I know of one instance of electrocution when a Millen HV connectors came apart and I know of several people who have had severe shocks from them.

Type HN connectors are good for HV, if you want to use RG-8.

SHV connectors are probably the safest as Gudmund has said, however they are expensive.

MHV's are much lower cost (~ 1/4 the price) and are safe with the following precautions.

1. Always have a second ground path to avoid the problem Gudmund described.

2. Use the female socket (UG-931/U) only as the receptacle on the RF deck. Do not put UG-931/U chassis mounts on your HV PS as it is possible to contact the center pin causing a shock. Use a RG-59 HV cable that exits the HV PS through a strain relief and a UG-932 male plug on the end of it.

3. Only used solid dielectric RG-59 for the HV cable. Foam cables can have center conductor migration causing arcs in the cable.

4. Although MHV and SHV connectors are rated for 5KV, that is pushing RG-59 at that voltage. If I remember right, I read some fine print on MHV / SHV specifications and 5KV was only allowed for low current applications, something like 100 ma. if I remember right. I recommend using less than 4KV.

5. NEVER connect or disconnect a HV connector with HV on it.

On 16-May-2003 OZ5IQ wrote:
Have in mni years been using the SC ( Screewed C-connector) at 4.5 KV in conjunction with a piece of RG213 / RG 8 and never had any failure.

Several manufators do have this connector and plug.

On 18-May-2003 G4AFJ wrote:
PET connectors are used on UK Atomic Energy Authority equipment often found on the surplus market so ready made up leads and sockets can be found at UK rallies often for very little money. These are, of course, used for HV supplies on Geiger-Muller counters and the like for HT feeds!

On 18-May-2003 G3SEK wrote:
G4AFJ wrote:
>PET connectors are used on UK Atomic Energy Authority equipment often found on 
>the surplus market so ready made up leads and sockets can be found at UK 
>rallies often for very little money. These are, of course, used for HV supplies 
>on Geiger-Muller counters and the like for HT feeds!

There's not much ex-UKALELE equipment of that generation around any more. Gone are the days of hauling an officially purchased trailer-load of electronics scrap out of the Harwell gate, tied down (entirely for safety, you understand) with several metres of URM67!

However, modern nucleonics gear is still available surplus from time to time, often at very good prices because nobody knows what it's for.

The SHV range seems to have become the modern standard for HV nucleonics in Europe (Geoff G3NAQ must be the expert on this).

As Steve said, the PET100 connectors really aren't very clever (in spite of what a certain VHF DX book says). Don't ever buy them at new prices.

Likewise MHV is a poor buy because it's such an incompetent design for an HV connector... which is why SHV had to be invented, and at last they got it right.

The RS part numbers are 212-7416 and 212-7444, at

On 18-May-2003 G8TIC wrote:
The defacto-standard in the G8TIC/M0VHF/M0BAA shack (or tent when portable) is:

- BNC for RF up to 100W

- N-type for RF above 100W

- SHV for B+ (EHT) from power packs to amps using RG400 1/4" PTFE coax

- TNC for B- (return) from power packs to amps using RG58 coax

- PL259/SO239 (otherwise known as "crocadile plugs") are banned by me for both RF and DC [I shouldn't say that one G6YIN thinks that PTFE ones make good EHT connectors...]

As a result:

a) nothing can be plugged in to the wrong place

b) there are at least three earth paths between power packs and amplifiers

I stopped using PET100 connectors about 10 years ago, they tend to go short internally where the whiskers of the braid are trapped by the circlip after years of use/flexing and lead to an unwanted sudden discharge of your HT pack (and possibly broken meters) etc.

On 15-May-2015 W5THT wrote:
Bundling the HV (cable and connectors you choose) with the ground cable and control cable by wrapping it neatly with regular RED plastic electrician's phasing tape insures that the high voltage and RF can't be interconnected if you locate the chassis connectors where the HV cable won't reach the RF chassis connector because it is in a bundle.

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