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Delivery To UK Mainland £6.95 + VAT

Thank you for the support and service you provide. I look forward to working with you guys again in the new year!


To all at Acorn,

On behalf of myself, and our Service staff, thankyou for your continued support, and thankyou for going the extra mile last week; our Client is now extremely satisfied!


We have just purchased a SOLO kit from yourselves and I have say we have been very impressed with the service and support provided – thank you 



Please pass on my thanks to Lauren for sorting out my order yesterday, top class service yet again from your team.



Perfect service, thank you



Dear Lauren, very good and prompt services, thanks!

Wishing you have a Merry Christmas and a Happy New Year 2015!


Hi Dave,

The service and support from Emma and the other staff has been superb and as a new customer purchasing wise I will now be placing all orders with Acorn.

Andrew Sullivan

You’re the best, thanks!

Have a nice weekend.

Best regards / Met vriendelijke groet


Good Morning Emma,

I must say you are the best.  Normally I do not receive such fast replies from overseas suppliers, and that too complete with courier charges.

Have a nice day.



Again many thanks for your help and assistance.

System now fully back on line.

Andrew Kelly

Hi Dave,

Many thanks for your swift reply & valued advise. (great service)



Dear Sales,

Equipment arrived on the vessel at berth as arranged, thank you so much for your assistance.

Jaqueline Bernard

Dear Lauren,
Thank you so much and very glad to be your customer.
Juladit C.

Juladit C

Cheers Dave you're a star

Kind Regards



Installed these today, worked a treat.




Thank you all for your support on this project. We’ve worked well together in my opinion and would hope that we can do so again in the future.


Hi Lauren,

The below parts have just arrived! That was very quick and efficient!

Thankyou for organising that


Thanks to Lauren for helping resolve a problem.

She was helpful, efficient, and above all pleasant.

A real asset.


Good morning Emma,

Order has been well received yesterday, I can say that we are very happy with your service.

Best regards,


Hello Aleks and Dave

Many thanks firstly for the quick response.

Once again many thanks for such a great turnaround.

Dave Lewis

Hi Deborah

Thank you very much for going extra mile for me. Great!

Best Regards


Dear Hannah,

After several weeks of trying to find these parts; you located part numbers, cost, availability and air freight within one day!

Nancy Johnson

I received and checked through my order today and everything is as it should be.

Thanks again to you and to Acorn fire and security for a great and efficient service.


Hi Lauren,

Thank you very much, excellent service as usual.



Thankyou so much for your assistance, I don't know how you managed to source this equipment, but I'm very glad you did. All fitted and working now!!

Med vennlig hilsen

K Larsen

Hi Dave

Just a quick note to say thanks for the advice on the replacement of the Mother board. We attended a week ago and all went smoothly, no problems since (touch wood!).



Thanks for all your help with this last night we appreciate the service you provided to us.

Kind Regards


Hi Emma,

Thank you very much for all your help - excellent service!

Fiona McGregor

Thanks Lauren,

it’s so nice to deal with a company who are so accommodating, it’s been a refreshing change for us!


Hi Hannah,

Thank you very much for the quick turnaround, as this was a big ask in a short space of time. Please convey my appreciation to all involved.

Steve Sneddon

Hello again,

Equipment arrived on MT as arranged.......amazing.

Marios Georgiades


dziękuję za doskonałą obsługę

systemu przeciwpozarowego i za wspaniale wsparcie.


Thanks Charlotte.

I wish all suppliers where as efficient and quick as you guys.

Best Regards,

Peter Jackson

Ms Deborah

We are extremely grateful and appreciative of yours and your team’s customer oriented attitude and behavior.

We look forward to further business dealings with your organization.



Many thanks to you and Aleks it is a great help.



Dear Hannah,

The test equipment arrived one day early, received on Tuesday; wunderbar!

Jürgen Schulz

Hi Emma,

Thank you for your awesome work!

William J


Ashley you're like a salesman dream!!

Thanks for your help Ash.

Kindest regards,


Hi Emma

Many thanks for your quick response. Just discovered your website today but it looks excellent!

Nicola Allan


Thanks for all your help and excellent customer service! :-)

Kind Regards,

Ainsley Cooper

Hi Dave,

One happy customer, thanks for the assistance with this.


Many thanks as always for the quality and speed of the service!


Dear Sirs,

Just a line to thank you for the prompt delivery of my JSB terminators which arrived at 09:00 today.


Stuart Willcock

Acorn Fire & Security have vastly improved our business, through excellent customer service from point of order, through to rapid delivery to our Engineers in the field.

Steven Troy

Thanks a lot,  we really appreciate professional work and good service.

We also wish you a Merry Christmas and Happy new year!


Hochiki MTL 7787+ Zener Barrier

Hochiki MTL 7787+ Zener Barrier


Product Code: MTL7787

Please Contact Us for Price & Availability.

Contact Us

Hochiki MTL 7787+ Zener Barrier 

Model MTL7787+ is an intrinsically safe, zone-powered, Zener-diode barrier for use in conventional fire detection systems for protection within hazardous areas. Model MTL7787+ is certified 'ia' for all zones and 'IIC' for all explosive atmospheres.


  • Simple installation onto standard DIN railing
  • Removable colour-coded terminals for easy connection
  • Accommodates conductors up to 2.5 sq mm
  • Supports up to two zones of I.S. products
  • Enclosure (box) available - DX070
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